The GitHub page for Thunderbird Android locks issues from being created that aren't bug reports: https://github.com/thunderbird/thunderbird-android/issues
There are a lot of people who use GitHub but don't want to sign up for a Mozilla account just to propose new ideas for open source repos. Mozilla should open discussion with its community there. Locking it down to getting feedback from only those with Mozilla accounts means you're only hearing and interacting with a very small subset of your users.
