Installing and updating the src tree with svn went like this [for release 12.2] into the src directory:
svn checkout https://svn.freebsd.org/base/releng/12.2 /usr/src
For Freebsd-Current [currently version 13] it is:
svn checkout https://svn.freebsd.org/base/head /usr/src
Updating the src...
Is there something similar to xref or cxref for the source code in FreeBSD? I used cscope which isn't bad, but that seems to be purely interactive. I'd like to be able to create a listing of cross references that I can print out and study.