Um, yeah, that's a problem... 
Try ubus call rpc-sys packagelist on an apk snapshot (I've been working on that for a few days, but there are underlying issues that I have yet to overcome == ABI versioning is different so the package lists are incompatible).
And the snapshot builds aren't producing a parseable package index yet, so the ASU tools just fail ( Should have indexes soon.auc, owut and LuCI ASU app).