>Are there any plans to have one built-in to FreeSWITCH?

Writing your own is a great exercise for sure but can be a lot of work to get right.
After getting a protocol parser/handler working you have to deal with the async programming aspect - picking a framework for it / wrapping it in a sensible higher level API, etc.

>I bet that the whole community is likely coding their own ESL handlers or at less I was

There's already a ton of mature projects for many languages (and frameworks within each language) so I don't know if that would be true (anymore).
Currently the only place I've found that provides any kind of definitive list is the wiki.

This is in fact the reason we've created the `friends-of-freeswitch` group - to try and gather at least the smaller projects on GitHub (and their authors) into one spot.

By FreeSWITCH? Yes. The CI (which runs for each new change set) spawns the latest FS docker image from the sources and switchio runs its full test suite against it.

In fact, there are tests disabled in switchio due to bugs discovered in FS / ESL (which we should really report).

Hope that helps :)