@Gargron I got my hands on Mastodon's source code, which is open to everyone, and learned every bit of how it works.
Therefore, I am able to provide services using Mastodon with confidence and respond to bugs immediately and provide feedback on them. I maintain my own forked source code while suggesting features to be included in the future.
The Mastodon community is very strong, as developers are born from the users and participate in the development to ensure quality and build the future.