Used in AIS net trackers from aliexpress. http://web.archive.org/web/20210809180746/https://pbs.twimg.com/media/Ex3FZafUcAIMJLL?format=jpg&name=4096x4096
This page says Si4483, but that appears to be a MOSFET part number. They probably meant 4463. Si4463 used in another one of these.
Maiana seems to have used various Si44xx chips in various versions. I think Si4463 in the latest, previously Si4460 and Si4467.
Difference between 60/61/63 seems to just be output power. 63 is the most at 100mW. SI4463-C2A-GM(R) seems to be current highest powered one. R on end of part number just means tape and reel.
Somewhat confusing / wrong document specifies which versions cover AIS range.
https://www.silabs.com/documents/public/application-notes/AN897.pdf
Looks like C2A and A2A are ok, B1B is not.