Questions or comments for the Git community can be sent to the mailing list by using the email address firstname.lastname@example.org. Bug reports for git should be sent to this mailing list.
You do not need to subscribe: you will be Cc'd in replies. Please keep the Cc list intact when replying (use "Reply to all"). Greylisting may delay your first post for a few hours. Note also that the list only accepts plain-text email; please disable HTML in your outgoing messages.
Windows-specific questions can also be sent to the Git for Windows mailing list (if in doubt whether your question is Windows-specific, just use the general Git mailing list). Please submit Windows-specific bugs to Git for Windows' bug tracker.
There is also Git user mailing list on Google Groups which is a nice place for beginners to ask about anything. If you're a downstream packager of Git, consider joining the Git packagers mailing list for low-volume announcements from the developers, as well as other discussion related to packaging & porting Git.
Bugs in git can be reported directly to the mailing list (see above for
details). Note that you do not need to subscribe to the list to send
to it. You can help us out by attempting to reproduce the bug in the latest
released version of git, or if you're willing to build git from source, the
Sometimes an attempted fix may be pending in this branch, in which case
your feedback as to whether the fix worked for you will be appreciated.
If you are new to submitting bugs, you might find this guide helpful for producing useful bug reports.
Reporting Security Issues
Issues which are security relevant should be disclosed privately to the Git Security mailing list.
If the manpages and this book aren’t enough and you need in-person help, you can try the #git channel on the Freenode IRC server (irc.freenode.net). These channels are regularly filled with hundreds of people who are all very knowledgeable about Git and are often willing to help. The #git-devel channel welcomes Git development discussion, and might be able to help you contribute to Git.
If you need specific help about one of the for-profit Git hosting sites, you might try their own IRC channels (such as #github or #gitlab) on the same IRC server.
Contributing to Git
The Documentation directory in the Git source code has several files of interest to developers who are looking to help contribute. After reading the coding guidelines, you can learn how to submit patches. For those looking to get more deeply involved, there is a howto for Git maintainers.