Advertise the webextension outside the various stores
Most likely on https://snowflake.torproject.org/
To upload designs, you'll need to enable LFS and have admin enable hashed storage. More information
GitLab is used only for code review, issue tracking and project management. Canonical locations for source code are still https://gitweb.torproject.org/ https://git.torproject.org/ and git-rw.torproject.org.
Most likely on https://snowflake.torproject.org/