Document search debounce time via setting #12121 (@fcollonval)
Improve toggled button styles in debugger. #12120 (@fcollonval)
Support dynamic toolbar definition #12078 (@fcollonval)
Debounce kernel sources filter #12068 (@fcollonval)
Settings UI gives an unreadable JSON dump #12064 (@fcollonval)
Polish settings editor #12061 (@fcollonval)
Show pause on exception button when not available and change caption … #12005 (@andrewfulton9)
Fix contrast in dark theme of settings editor #12004 (@krassowski)
Fix for kernel reconnect #11952 (@3coins)
Add settings UI #11977 (@fcollonval)
Show the kernel sources as a debugger tab and allow the user to break in kernel sources #11954 (@echarles)
Enable not showing editor for read-only Markdown cells #11950 (@fcollonval)
Add side-by-side margin override in the notebookConfig #11880 (@echarles)
Add additional Accel Enter keyboard shortcuts for the notebook:run-cell command #11942 (@jtpio)
Add execution progress indicator #11941 (@trungleduc)
Allow to link factory to file type when adding it #11540 (@fcollonval)
Pause on exception #11923 (@andrewfulton9)
Increase color contrast in input boxes #11922 (@fcollonval)
Add startMode setting to define the startup mode #11881 (@echarles)
Update variable renderer panels #11874 (@fcollonval)
Allow extensions and users to customize easily toolbar items. #11873 (@fcollonval)
Add debugger variable renderer based on mime type #11871 (@fcollonval)
Add a command to open a file from a URL #11870 (@fcollonval)
List workspaces #11869 (@fcollonval)
Add closeOnExit terminal option #11868 (@fcollonval)
Mentions pip3 for macOS users in docs #11848 (@JasonWeill)
Toc running cell indicator #11804 (@andrewfulton9)
Fix overlapped shadow for scrolling output cell #11785 (@thesinepainter)
Toggle side-by-side rendering for current notebook (#11793) #11794 (@fcollonval)

Bugs fixed

Build UMD module for @jupyterlab/services #12141 (@fcollonval)
Fix broken link in docs #12138 (@JasonWeill)
Fix: Select kernel text (when open a no kernel .ipynb file) is not translated correctly (#12133) #12135 (@yangql176)
Opening keyboard shortcuts UI result in "destruction" of shortcut settings #12112 (@fcollonval)
Fix error rendering in Advanced Settings Editor #12107 (@krassowski)
Fix json schema for kernel status settings #11451 (@fcollonval)
Remove toolbar factory setting trick in the tests #12096 (@jtpio)
Log error on open document widget. #12080 (@trungleduc)
update status to unknown when kernel is shutdown from running kernels tab #12083 (@akshaychitneni)
Handle shutdown error #12048 (@Zsailer)
use path-like comparison in initialize_templates() #12024 (@kellyyke)
Fix misaligned icon and checkbox of setting editor #11976 (@trungleduc)
overrides.json definition takes precedence #11610 (@fcollonval)
Adjust z-index of execution progress tooltip #11973 (@Sync271)
Fix the debug modules model #11967 #11968 (@echarles)
Fix autocomplete in console #11949 (@fcollonval)
fix(docprovider): fix issue with empty notebook #11901 (@entropitor)
Ensure a single modal is opened in case of time conflict savings #11883 (@echarles)
Restore line number state when stopping debugger #11768 (@fcollonval)
Backport PR #11852 on branch 3.3.x (Add percent decoding to username) #11865 (@fcollonval)
Fix Handling of WebSocket Startup Errors #11358 (@blink1073)
Specify an output hash function for Galata #11830 (@jasongrout)
Preserve breakpoint gutter when cells are moved. #11766 (@fcollonval)

Maintenance and upkeep improvements

Parse URL parameters in user model #12065 (@fcollonval)
Update vscode-debugprotocol to @vscode/debugprotocol #11953 (@fcollonval)
Partly backport PR #11388 on branch 3.3.x (Add update galata snapshot step) #11927 (@fcollonval)
Use maintainer-tools base setup action #11595 (@jtpio)
Drop testing Python 3.6, test on Python 3.10 #11867 (@fcollonval)
Drop support for Python 3.6 #11740 (@jtpio)
Use the root yarn.lock in staging when making a release. #11433 (@jasongrout)
Update reference snapshot for the completer UI test #11846 (@jtpio)
Bump version for the 3.3 prerelease #11810 (@jtpio)

Documentation improvements

Fix broken link in docs #12138 (@JasonWeill)
Fix anchors and myst configuration #12063 (@fcollonval)
docs: fix shell command with unquoted '>' #12002 (@ErikBjare)
Update screenshots and text for user interface docs #11982 (@fcollonval)
Update several extensions readme files to delete old content. #11947 (@jasongrout)
Remove theme cookiecutter from the docs #11928 (@jtpio)
Allow extensions and users to customize easily toolbar items. #11873 (@fcollonval)
Mentions pip3 for macOS users in docs #11848 (@JasonWeill)
Add 3.1.19 Changelog Entry #11842 (@jtpio)
Give conda instructions for the pixman pkg-config error. #11829 (@jasongrout)