The Mozilla build VM is no longer maintained or supported. Thanks to significant improvements in our build environment setup process, it's much simpler and easier to get set up and stay up to date by starting with Building Firefox instead.
Other links of interest may include:
- Developer guide (documentation about developing on and for Mozilla projects).
- Mentored bugs have a mentor who commits to helping you every step of the way. Generally, there should be enough information in the bug to get started. Whenever you need help, contact the mentor via Matrix, in the bug itself, or by email. When you've completed the bug, they will help you get your code into the tree.
- "Good" first bugs may be a little stale, but at some point in their lives we considered that they would be a good first step for newcomers to Mozilla. We are in the process of migrating these bugs to mentored bugs, but more recent "good first bugs" may be good starting points if there are no appropriate mentored bugs.
You can also ask your getting-started questions in the Introduction chat room on Matrix, and any Firefox development questions in the developers room.