Released today (25/6/2021) by XIEGUs worldwide distributor Radioddity is this manual: CAT control your Xiegu G90 with your PC and start operating in digital modes https://radioddity.s3.amazonaws.com/Radioddity - Xiegu G90, CAT and Digital modes V1.0_20210623.pdf 73 Ed DD5LP
The table of CAT (CiV) controls in the new document is not 100% correct - some of the commands listed simply don't work (yet?) - in any case - here is the list of fully tested commands. 73 Ed.