Hello, I already answered in the pull request.
Sad that you spent so much time on that.
Actually it's much easier: Edit the .ioc and the project files, replace all 101CBTx entries with 103RBTx, copy and edit the linker script, changing the line that sets the RAM size, update the project linker settings to use that file, and done!
It's a good idea to ask before doing such things, didn't you wonder why there wasn't a RB profile?
There's no 64 pin build anymore, because there's no need to do so, I unified v2 and v3 builds using 101CB because everything is compatible. Less mess with files.
I will never have a build for each stm32 type (101c,102c,103c,101r,102r,103r...) and every controller type (v1.5, v2,v3).
Multiply that, and make these builds by hand every time. That's a lot of work, and why? The result will be the same. The project needs to be compatible with all, so it's designed to use 10KB max.
The extra RAM will do nothing, there isn't any benefit.
48 and 64pin boards use the same pins, so it's just a waste of time.
Flash the current v3.x build in your RB, and you'll see...