FL Keys
Tiny House Guy in the Florida Keys
Just saw this on the Aliexpress page (can't believe I missed it the first time!). You were right. It is RS485. Just not sure how it it used.This connector is labelled "B A" which is probably for RS485.
Edit: hmm... actually it's probably not as RS485 require a ground in addition to the two signal lines.
@OverkillSolar Thanks for chiming in. If you don't know what it's for, I guess I'm giving up.