Combust is a bit of Perl code to help run websites. Once upon a time in the early 2000s it helped smoothe over the mod_perl APIs. Since then we got Plack and other deliciousness. Combust now uses Plack, but all the smoothing over is just extra abstractions and under-documented "helpers" that are fine for things already using it, but a little crazy if you aren't already.
If you are making something new in Perl you probably want Mojolicious.
See https://github.com/abh/combust or the Combust website at http://combust.develooper.com/
Combust is Copyright 2003-2009 Ask Bjørn Hansen. See the LICENSE file.