diff --git a/app/models/group.rb b/app/models/group.rb
index c38ddbdf6fb..ea9091455ac 100644
--- a/app/models/group.rb
+++ b/app/models/group.rb
@@ -172,6 +172,10 @@ class Group < Namespace
     notification_settings(hierarchy_order: hierarchy_order).where(user: user)
   end
 
+  def packages_feature_enabled?
+    ::Gitlab.config.packages.enabled
+  end
+
   def notification_email_for(user)
     # Finds the closest notification_setting with a `notification_email`
     notification_settings = notification_settings_for(user, hierarchy_order: :asc)
diff --git a/app/models/project.rb b/app/models/project.rb
index 3aa0db56404..32f9b580b47 100644
--- a/app/models/project.rb
+++ b/app/models/project.rb
@@ -838,6 +838,10 @@ class Project < ApplicationRecord
     auto_devops_config[:scope] != :project && !auto_devops_config[:status]
   end
 
+  def has_packages?(package_type)
+    packages.where(package_type: package_type).exists?
+  end
+
   def first_auto_devops_config
     return namespace.first_auto_devops_config if auto_devops&.enabled.nil?
 
diff --git a/app/services/groups/transfer_service.rb b/app/services/groups/transfer_service.rb
index fbbf4ce8baf..885f5c1edd0 100644
--- a/app/services/groups/transfer_service.rb
+++ b/app/services/groups/transfer_service.rb
@@ -46,6 +46,21 @@ module Groups
       raise_transfer_error(:namespace_with_same_path) if namespace_with_same_path?
       raise_transfer_error(:group_contains_images) if group_projects_contain_registry_images?
       raise_transfer_error(:cannot_transfer_to_subgroup) if transfer_to_subgroup?
+      raise_transfer_error(:group_contains_npm_packages) if group_with_npm_packages?
+    end
+
+    def group_with_npm_packages?
+      return false unless group.packages_feature_enabled?
+
+      npm_packages = ::Packages::GroupPackagesFinder.new(current_user, group, package_type: :npm).execute
+
+      return true if different_root_ancestor? && npm_packages.exists?
+
+      false
+    end
+
+    def different_root_ancestor?
+      group.root_ancestor != new_parent_group&.root_ancestor
     end
 
     def group_is_already_root?
@@ -133,7 +148,8 @@ module Groups
         same_parent_as_current: s_('TransferGroup|Group is already associated to the parent group.'),
         invalid_policies: s_("TransferGroup|You don't have enough permissions."),
         group_contains_images: s_('TransferGroup|Cannot update the path because there are projects under this group that contain Docker images in their Container Registry. Please remove the images from your projects first and try again.'),
-        cannot_transfer_to_subgroup: s_('TransferGroup|Cannot transfer group to one of its subgroup.')
+        cannot_transfer_to_subgroup: s_('TransferGroup|Cannot transfer group to one of its subgroup.'),
+        group_contains_npm_packages: s_('TransferGroup|Group contains projects with NPM packages.')
       }.freeze
     end
   end
diff --git a/app/services/groups/update_service.rb b/app/services/groups/update_service.rb
index 948540619ae..81393681dc0 100644
--- a/app/services/groups/update_service.rb
+++ b/app/services/groups/update_service.rb
@@ -17,6 +17,8 @@ module Groups
 
       return false unless valid_share_with_group_lock_change?
 
+      return false unless valid_path_change_with_npm_packages?
+
       before_assignment_hook(group, params)
 
       group.assign_attributes(params)
@@ -36,6 +38,20 @@ module Groups
 
     private
 
+    def valid_path_change_with_npm_packages?
+      return true unless group.packages_feature_enabled?
+      return true if params[:path].blank?
+      return true if !group.has_parent? && group.path == params[:path]
+
+      npm_packages = ::Packages::GroupPackagesFinder.new(current_user, group, package_type: :npm).execute
+      if npm_packages.exists?
+        group.errors.add(:path, s_('GroupSettings|cannot change when group contains projects with NPM packages'))
+        return
+      end
+
+      true
+    end
+
     def before_assignment_hook(group, params)
       # overridden in EE
     end
diff --git a/app/services/projects/transfer_service.rb b/app/services/projects/transfer_service.rb
index 60e5b7e2639..0fb70feec86 100644
--- a/app/services/projects/transfer_service.rb
+++ b/app/services/projects/transfer_service.rb
@@ -55,10 +55,18 @@ module Projects
         raise TransferError.new(s_('TransferProject|Project cannot be transferred, because tags are present in its container registry'))
       end
 
+      if project.has_packages?(:npm) && !new_namespace_has_same_root?(project)
+        raise TransferError.new(s_("TransferProject|Root namespace can't be updated if project has NPM packages"))
+      end
+
       attempt_transfer_transaction
     end
     # rubocop: enable CodeReuse/ActiveRecord
 
+    def new_namespace_has_same_root?(project)
+      new_namespace.root_ancestor == project.namespace.root_ancestor
+    end
+
     def attempt_transfer_transaction
       Project.transaction do
         project.expire_caches_before_rename(@old_path)
diff --git a/doc/administration/packages/container_registry.md b/doc/administration/packages/container_registry.md
index 44f1d075a5e..4933a9dab5d 100644
--- a/doc/administration/packages/container_registry.md
+++ b/doc/administration/packages/container_registry.md
@@ -693,6 +693,35 @@ notifications:
       backoff: 1000
 ```
 
+## Run the Cleanup policy now
+
+To reduce the amount of [Container Registry disk space used by a given project](../troubleshooting/gitlab_rails_cheat_sheet.md#registry-disk-space-usage-by-project),
+administrators can clean up image tags
+and [run garbage collection](#container-registry-garbage-collection).
+
+To remove image tags by running the cleanup policy, run the following commands in the
+[GitLab Rails console](../troubleshooting/navigating_gitlab_via_rails_console.md):
+
+```ruby
+# Numeric ID of the project whose container registry should be cleaned up
+P = <project_id>
+
+# Numeric ID of a developer, maintainer or owner in that project
+U = <user_id>
+
+# Get required details / objects
+user    = User.find_by_id(U)
+project = Project.find_by_id(P)
+repo    = ContainerRepository.find_by(project_id: P)
+policy  = ContainerExpirationPolicy.find_by(project_id: P)
+
+# Start the tag cleanup
+Projects::ContainerRepository::CleanupTagsService.new(project, user, policy.attributes.except("created_at", "updated_at")).execute(repo)
+```
+
+NOTE: **Note:**
+You can also [run cleanup on a schedule](../../user/packages/container_registry/index.md#cleanup-policy).
+
 ## Container Registry garbage collection
 
 NOTE: **Note:**
diff --git a/doc/administration/troubleshooting/gitlab_rails_cheat_sheet.md b/doc/administration/troubleshooting/gitlab_rails_cheat_sheet.md
index 8e9749fb239..097374e1801 100644
--- a/doc/administration/troubleshooting/gitlab_rails_cheat_sheet.md
+++ b/doc/administration/troubleshooting/gitlab_rails_cheat_sheet.md
@@ -689,10 +689,10 @@ end
 As a GitLab administrator, you may need to reduce disk space consumption.
 A common culprit is Docker Registry images that are no longer in use. To find
 the storage broken down by each project, run the following in the
-GitLab Rails console:
+[GitLab Rails console](../troubleshooting/navigating_gitlab_via_rails_console.md):
 
 ```ruby
-projects_and_size = []
+projects_and_size = [["project_id", "creator_id", "registry_size_bytes", "project path"]]
 # You need to specify the projects that you want to look through. You can get these in any manner.
 projects = Project.last(100)
 
@@ -707,17 +707,21 @@ projects.each do |p|
    end
 
    if project_total_size > 0
-      projects_and_size << [p.full_path,project_total_size]
+      projects_and_size << [p.project_id, p.creator.id, project_total_size, p.full_path]
    end
 end
 
 # projects_and_size is filled out now
 # maybe print it as comma separated output?
 projects_and_size.each do |ps|
-   puts "%s,%s" % ps
+   puts "%s,%s,%s,%s" % ps
 end
 ```
 
+### Run the Cleanup policy now
+
+Find this content in the [Container Registry troubleshooting docs](../packages/container_registry.md#run-the-cleanup-policy-now).
+
 ## Sidekiq
 
 This content has been moved to the [Troubleshooting Sidekiq docs](./sidekiq.md).
diff --git a/doc/user/project/merge_requests/img/comment-on-any-diff-line.png b/doc/user/project/merge_requests/img/comment-on-any-diff-line.png
index 5b9844bf02f..b5c4b12a6a7 100644
Binary files a/doc/user/project/merge_requests/img/comment-on-any-diff-line.png and b/doc/user/project/merge_requests/img/comment-on-any-diff-line.png differ
diff --git a/doc/user/project/merge_requests/img/multiline-comment-highlighted.png b/doc/user/project/merge_requests/img/multiline-comment-highlighted.png
new file mode 100644
index 00000000000..c254af06c8f
Binary files /dev/null and b/doc/user/project/merge_requests/img/multiline-comment-highlighted.png differ
diff --git a/doc/user/project/merge_requests/img/multiline-comment-saved.png b/doc/user/project/merge_requests/img/multiline-comment-saved.png
new file mode 100644
index 00000000000..6c44ee9f777
Binary files /dev/null and b/doc/user/project/merge_requests/img/multiline-comment-saved.png differ
diff --git a/doc/user/project/merge_requests/reviewing_and_managing_merge_requests.md b/doc/user/project/merge_requests/reviewing_and_managing_merge_requests.md
index 91ca48f85d5..d87e9f3daa8 100644
--- a/doc/user/project/merge_requests/reviewing_and_managing_merge_requests.md
+++ b/doc/user/project/merge_requests/reviewing_and_managing_merge_requests.md
@@ -141,10 +141,52 @@ whitespace changes.
 > [Introduced](https://gitlab.com/gitlab-org/gitlab-foss/-/issues/13950) in GitLab 11.5.
 
 GitLab provides a way of leaving comments in any part of the file being changed
-in a Merge Request. To do so, click the **...** button in the gutter of the Merge Request diff UI to expand the diff lines and leave a comment, just as you would for a changed line.
+in a Merge Request. To do so, click the **{comment}** **comment** icon in the gutter of the Merge Request diff UI to expand the diff lines and leave a comment, just as you would for a changed line.
 
 ![Comment on any diff file line](img/comment-on-any-diff-line.png)
 
+### Commenting on multiple lines
+
+> - [Introduced](https://gitlab.com/gitlab-org/ux-research/-/issues/870) in GitLab 13.2.
+> - It's deployed behind a feature flag, enabled by default.
+> - It's enabled on GitLab.com.
+> - It's able to be enabled or disabled per-project
+> - It's recommended for production use.
+> - For GitLab self-managed instances, GitLab administrators can opt to [enable it](#enable-or-disable-multiline-comments-core-only). **(CORE ONLY)**
+
+GitLab provides a way to select which lines of code a comment refers to. After starting a comment
+a dropdown selector is shown to select the first line that this comment refers to.
+The last line is the line that the comment icon was initially clicked on.
+
+New comments default to single line comments by having the first and last lines
+the same. Selecting a different starting line turns this into a multiline comment.
+
+![Multiline comment selection highlighted](img/multiline-comment-highlighted.png)
+
+Once a multiline comment is saved the lines of code pertaining to that comment are listed directly
+above it.
+
+![Multiline comment selection displayed above comment](img/multiline-comment-saved.png)
+
+### Enable or disable multiline comments **(CORE ONLY)**
+
+The multiline comments feature is under development but ready for production use.
+It is deployed behind a feature flag that is **enabled by default**.
+[GitLab administrators with access to the GitLab Rails console](../../../administration/feature_flags.md)
+can opt to disable it for your instance.
+
+To disable it:
+
+```ruby
+Feature.disable(:multiline_comments)
+```
+
+To enable it:
+
+```ruby
+Feature.enable(:multiline_comments)
+```
+
 ## Pipeline status in merge requests widgets
 
 If you've set up [GitLab CI/CD](../../../ci/README.md) in your project,
diff --git a/spec/lib/banzai/reference_parser/base_parser_spec.rb b/spec/lib/banzai/reference_parser/base_parser_spec.rb
index 0eea51262ba..5ab76b2c68b 100644
--- a/spec/lib/banzai/reference_parser/base_parser_spec.rb
+++ b/spec/lib/banzai/reference_parser/base_parser_spec.rb
@@ -8,13 +8,14 @@ RSpec.describe Banzai::ReferenceParser::BaseParser do
   let(:user) { create(:user) }
   let(:project) { create(:project, :public) }
   let(:context) { Banzai::RenderContext.new(project, user) }
-
-  subject do
-    klass = Class.new(described_class) do
+  let(:parser_class) do
+    Class.new(described_class) do
       self.reference_type = :foo
     end
+  end
 
-    klass.new(context)
+  subject do
+    parser_class.new(context)
   end
 
   describe '.reference_type=' do
@@ -43,12 +44,20 @@ RSpec.describe Banzai::ReferenceParser::BaseParser do
     let(:link) { empty_html_link }
 
     context 'when the link has a data-project attribute' do
-      it 'checks if user can read the resource' do
+      before do
         link['data-project'] = project.id.to_s
+      end
 
-        expect(subject).to receive(:can_read_reference?).with(user, project, link)
+      it 'includes the link if can_read_reference? returns true' do
+        expect(subject).to receive(:can_read_reference?).with(user, project, link).and_return(true)
 
-        subject.nodes_visible_to_user(user, [link])
+        expect(subject.nodes_visible_to_user(user, [link])).to contain_exactly(link)
+      end
+
+      it 'excludes the link if can_read_reference? returns false' do
+        expect(subject).to receive(:can_read_reference?).with(user, project, link).and_return(false)
+
+        expect(subject.nodes_visible_to_user(user, [link])).to be_empty
       end
     end
 
@@ -178,58 +187,56 @@ RSpec.describe Banzai::ReferenceParser::BaseParser do
     it 'gathers the references for every node matching the reference type' do
       dummy = Class.new(described_class) do
         self.reference_type = :test
+
+        def gather_references(nodes)
+          nodes
+        end
       end
 
-      instance = dummy.new(Banzai::RenderContext.new(project, user))
-      document = Nokogiri::HTML.fragment('<a class="gfm"></a><a class="gfm" data-reference-type="test"></a>')
+      instance = dummy.new(context)
+      document_a = Nokogiri::HTML.fragment(<<-FRAG)
+      <a class="gfm">one</a>
+      <a class="gfm" data-reference-type="test">two</a>
+      <a class="gfm" data-reference-type="other">three</a>
+      FRAG
+      document_b = Nokogiri::HTML.fragment(<<-FRAG)
+      <a class="gfm" data-reference-type="test">four</a>
+      FRAG
+      document_c = Nokogiri::HTML.fragment('')
 
-      expect(instance).to receive(:gather_references)
-        .with([document.children[1]])
-        .and_return([user])
-
-      expect(instance.process([document])).to eq([user])
+      expect(instance.process([document_a, document_b, document_c]))
+        .to contain_exactly(document_a.css('a')[1], document_b.css('a')[0])
     end
   end
 
   describe '#gather_references' do
-    let(:link) { double(:link) }
+    let(:nodes) { (1..10).map { |n| double(:link, id: n) } }
 
-    it 'does not process links a user can not reference' do
-      expect(subject).to receive(:nodes_user_can_reference)
-        .with(user, [link])
-        .and_return([])
+    let(:parser_class) do
+      Class.new(described_class) do
+        def nodes_user_can_reference(_user, nodes)
+          nodes.select { |n| n.id.even? }
+        end
 
-      expect(subject).to receive(:referenced_by).with([])
+        def nodes_visible_to_user(_user, nodes)
+          nodes.select { |n| n.id > 5 }
+        end
 
-      subject.gather_references([link])
+        def referenced_by(nodes)
+          nodes.map(&:id)
+        end
+      end
     end
 
-    it 'does not process links a user can not see' do
-      expect(subject).to receive(:nodes_user_can_reference)
-        .with(user, [link])
-        .and_return([link])
-
-      expect(subject).to receive(:nodes_visible_to_user)
-        .with(user, [link])
-        .and_return([])
-
-      expect(subject).to receive(:referenced_by).with([])
-
-      subject.gather_references([link])
+    it 'returns referenceable and visible objects, alongside nodes that are referenceable but not visible' do
+      expect(subject.gather_references(nodes)).to match(
+        visible: contain_exactly(6, 8, 10),
+        not_visible: match_array(nodes.select { |n| n.id.even? && n.id <= 5 })
+      )
     end
 
-    it 'returns the references if a user can reference and see a link' do
-      expect(subject).to receive(:nodes_user_can_reference)
-        .with(user, [link])
-        .and_return([link])
-
-      expect(subject).to receive(:nodes_visible_to_user)
-        .with(user, [link])
-        .and_return([link])
-
-      expect(subject).to receive(:referenced_by).with([link])
-
-      subject.gather_references([link])
+    it 'is always empty if the input is empty' do
+      expect(subject.gather_references([])) .to match(visible: be_empty, not_visible: be_empty)
     end
   end
 
diff --git a/spec/models/project_spec.rb b/spec/models/project_spec.rb
index 8fdda241719..722bf77faed 100644
--- a/spec/models/project_spec.rb
+++ b/spec/models/project_spec.rb
@@ -6154,6 +6154,46 @@ RSpec.describe Project do
     end
   end
 
+  describe '#has_packages?' do
+    let(:project) { create(:project, :public) }
+
+    subject { project.has_packages?(package_type) }
+
+    shared_examples 'returning true examples' do
+      let!(:package) { create("#{package_type}_package", project: project) }
+
+      it { is_expected.to be true }
+    end
+
+    shared_examples 'returning false examples' do
+      it { is_expected.to be false }
+    end
+
+    context 'with maven packages' do
+      it_behaves_like 'returning true examples' do
+        let(:package_type) { :maven }
+      end
+    end
+
+    context 'with npm packages' do
+      it_behaves_like 'returning true examples' do
+        let(:package_type) { :npm }
+      end
+    end
+
+    context 'with conan packages' do
+      it_behaves_like 'returning true examples' do
+        let(:package_type) { :conan }
+      end
+    end
+
+    context 'with no package type' do
+      it_behaves_like 'returning false examples' do
+        let(:package_type) { nil }
+      end
+    end
+  end
+
   describe '#environments_for_scope' do
     let_it_be(:project, reload: true) { create(:project) }
 
diff --git a/spec/services/groups/transfer_service_spec.rb b/spec/services/groups/transfer_service_spec.rb
index fa254bba6a9..d21c59e24c8 100644
--- a/spec/services/groups/transfer_service_spec.rb
+++ b/spec/services/groups/transfer_service_spec.rb
@@ -8,6 +8,74 @@ RSpec.describe Groups::TransferService do
   let!(:group_member) { create(:group_member, :owner, group: group, user: user) }
   let(:transfer_service) { described_class.new(group, user) }
 
+  context 'handling packages' do
+    let(:group) { create(:group, :public) }
+    let(:project) { create(:project, :public, namespace: group) }
+    let(:new_group) { create(:group, :public) }
+
+    before do
+      group.add_owner(user)
+      new_group&.add_owner(user)
+    end
+
+    context 'with an npm package' do
+      before do
+        create(:npm_package, project: project)
+      end
+
+      shared_examples 'transfer not allowed' do
+        it 'does not allow transfer when there is a root namespace change' do
+          transfer_service.execute(new_group)
+
+          expect(transfer_service.error).to eq('Transfer failed: Group contains projects with NPM packages.')
+        end
+      end
+
+      it_behaves_like 'transfer not allowed'
+
+      context 'with a project within subgroup' do
+        let(:root_group) { create(:group) }
+        let(:group) { create(:group, parent: root_group) }
+
+        before do
+          root_group.add_owner(user)
+        end
+
+        it_behaves_like 'transfer not allowed'
+
+        context 'without a root namespace change' do
+          let(:new_group) { create(:group, parent: root_group) }
+
+          it 'allows transfer' do
+            transfer_service.execute(new_group)
+
+            expect(transfer_service.error).not_to be
+            expect(group.parent).to eq(new_group)
+          end
+        end
+
+        context 'when transferring a group into a root group' do
+          let(:new_group) { nil }
+
+          it_behaves_like 'transfer not allowed'
+        end
+      end
+    end
+
+    context 'without an npm package' do
+      context 'when transferring a group into a root group' do
+        let(:group) { create(:group, parent: create(:group)) }
+
+        it 'allows transfer' do
+          transfer_service.execute(nil)
+
+          expect(transfer_service.error).not_to be
+          expect(group.parent).to be_nil
+        end
+      end
+    end
+  end
+
   shared_examples 'ensuring allowed transfer for a group' do
     context "when there's an exception on GitLab shell directories" do
       let(:new_parent_group) { create(:group, :public) }
diff --git a/spec/services/groups/update_service_spec.rb b/spec/services/groups/update_service_spec.rb
index 25c79d9e600..1e6a8d53354 100644
--- a/spec/services/groups/update_service_spec.rb
+++ b/spec/services/groups/update_service_spec.rb
@@ -9,6 +9,50 @@ RSpec.describe Groups::UpdateService do
   let!(:public_group) { create(:group, :public) }
 
   describe "#execute" do
+    shared_examples 'with packages' do
+      before do
+        group.add_owner(user)
+      end
+
+      context 'with npm packages' do
+        let!(:package) { create(:npm_package, project: project) }
+
+        it 'does not allow a path update' do
+          expect(update_group(group, user, path: 'updated')).to be false
+          expect(group.errors[:path]).to include('cannot change when group contains projects with NPM packages')
+        end
+
+        it 'allows name update' do
+          expect(update_group(group, user, name: 'Updated')).to be true
+          expect(group.errors).to be_empty
+          expect(group.name).to eq('Updated')
+        end
+      end
+    end
+
+    context 'with project' do
+      let!(:group) { create(:group, :public) }
+      let(:project) { create(:project, namespace: group) }
+
+      it_behaves_like 'with packages'
+
+      context 'located in a subgroup' do
+        let(:subgroup) { create(:group, parent: group) }
+        let!(:project) { create(:project, namespace: subgroup) }
+
+        before do
+          subgroup.add_owner(user)
+        end
+
+        it_behaves_like 'with packages'
+
+        it 'does allow a path update if there is not a root namespace change' do
+          expect(update_group(subgroup, user, path: 'updated')).to be true
+          expect(subgroup.errors[:path]).to be_empty
+        end
+      end
+    end
+
     context "project visibility_level validation" do
       context "public group with public projects" do
         let!(:service) { described_class.new(public_group, user, visibility_level: Gitlab::VisibilityLevel::INTERNAL) }
@@ -238,4 +282,8 @@ RSpec.describe Groups::UpdateService do
       end
     end
   end
+
+  def update_group(group, user, opts)
+    Groups::UpdateService.new(group, user, opts).execute
+  end
 end
diff --git a/spec/services/projects/transfer_service_spec.rb b/spec/services/projects/transfer_service_spec.rb
index 72426a6f6ec..3362b333c6e 100644
--- a/spec/services/projects/transfer_service_spec.rb
+++ b/spec/services/projects/transfer_service_spec.rb
@@ -11,6 +11,39 @@ RSpec.describe Projects::TransferService do
 
   subject(:execute_transfer) { described_class.new(project, user).execute(group) }
 
+  context 'with npm packages' do
+    before do
+      group.add_owner(user)
+    end
+
+    subject(:transfer_service) { described_class.new(project, user) }
+
+    let!(:package) { create(:npm_package, project: project) }
+
+    context 'with a root namespace change' do
+      it 'does not allow the transfer' do
+        expect(transfer_service.execute(group)).to be false
+        expect(project.errors[:new_namespace]).to include("Root namespace can't be updated if project has NPM packages")
+      end
+    end
+
+    context 'without a root namespace change' do
+      let(:root) { create(:group) }
+      let(:group) { create(:group, parent: root) }
+      let(:other_group) { create(:group, parent: root) }
+      let(:project) { create(:project, :repository, namespace: group) }
+
+      before do
+        other_group.add_owner(user)
+      end
+
+      it 'does allow the transfer' do
+        expect(transfer_service.execute(other_group)).to be true
+        expect(project.errors[:new_namespace]).to be_empty
+      end
+    end
+  end
+
   context 'namespace -> namespace' do
     before do
       allow_next_instance_of(Gitlab::UploadsTransfer) do |service|