At the moment, the current syntax is a list of objects like this: [{"url":"example.com"}, {"url":"example.com1"}]. I haven't added wildcard or regex support yet. Check the Github page periodically; I'll be updating the wiki soon.

EDIT: v0.8.5 has support for regex. https://github.com/sereneblue/chameleon/wiki/Whitelist

I haven't tested this in the mobile version of Firefox. I'll see what I can do.

EDIT:
I just tested it with the mobile Firefox Nightly 57 & 60. I'm not sure what's causing issues, but I've opened an issue on Github. https://github.com/sereneblue/chameleon/issues/15

EDIT2:
Chameleon now works on Firefox for Android!