Here’s the announcement about Flapjack, a tool that I use to develop the libraries that make up Endless’s developer platform: https://ptomato.wordpress.com/2018/01/17/announcing-flapjack/
Flapjack can be used to make and test changes in libraries such as eos-knowledge-lib, xapian-glib, etc., finally providing a good answer to this question: https://community.endlessos.com/t/eos-knowledge-lib-require-some-help-in-building/5098
I’ve shared my Flapjack configuration files here, in case you want to try out the setup that I use for developing the Endless SDK Flatpak runtime: https://gist.github.com/ptomato/3f679bdeb77f3b788281afe9161209c8