[luatex] Documentation about callbacks missing?

[Deepak Jois]

On Mon, Apr 18, 2016 at 1:13 PM, luigi scarso <luigi.scarso at gmail.com> wrote:
> which chapter ?

I cannot find a chapter/section (not sure which) which describes how
to register a callback, and also documents the different callbacks
like post_linebreak_filter, hpack_filter, vpack_filter etc.

If I remember correctly, it used to be there in a previous manual I
had downloaded. The one I am looking at now was generated on Apr 13
2016, and that chapter/section is missing.

Deepak