Hello. In my source file, there are these features: pref, blwf, abvf, pstf, pres, blws, abvs, psts, clig (based on OpenType for Khmer script documentation from Microsoft.)
But when Khmer script is selected from the Features menu, all features are enabled, except abvf, pref, and clig. These three should be enabled too. What I expect when I selected a script is that all features having that script tag will be enabled accordingly.
Additionally, I wrote a short python code to get the feature list of the current tab (while Khmer script is still selected), and I got all these features: blwm, akhn, blws, pres, abvm, psts, cjct, nukt, pref, blwf, abvs, haln, pstf, half, rkrf, vatu.
I don’t think akhn, cjct, kukt, haln, rkrf, and vatu have anything to do with Khmer script.