SVN official docs are at https://subversion.apache.org/docs/. They link to https://svnbook.red-bean.com/ which is still on 1.7 for stable and 1.8 for the draft, whereas Subversion itself is on 1.14 (which came out in 2020, no further stable versions yet as of this writing in mid-2023). This leaves some gaps . . .
Notably, some nice cleanup stuff has been added to SVN since. For example this extensive cleanup line used in scripts at GMCL:
```
svn cleanup . --include-externals --remove-unversioned --remove-ignored --non-interactive --vacuum-pristines
```
The redbook [[ https://svnbook.red-bean.com/nightly/en/svn.ref.svn.c.cleanup.html | only mentions `--diff3-cmd` as an option, which is to say all five options @keithzg is using there aren't in the SVN manual. Helpful! Hopefully they are obvious to you and you don't need any other ones ;)