PRTG Alerted me to a disk space issue on one of my servers.
After a bit of investigation there was 10GB+ in use in:
And this was growing pretty steadily.
I found a few solutions, one was to just delete the folder, the other was to have a script that ran daily to delete old log files, which for reference is:
C:\Windows\System32\forfiles.exe /p " C:\Users\AAD_00aa00a00000\AppData\Local\Microsoft\MSOIdentityCRL\Tracing " /s /m *.* /c "cmd /c Del @path" /d -7
So, batch file, scheduled task, job done. Now it sits at about 1GB.