none of which we use

Which one do you use?

Personally, even though I’ve added NppExec scripts that can add and commit files to my SVN repos, I find that the vast majority of my SVN-ing occurs in Windows Explorer TortoiseSVN extensions or the command line, rather than inside Notepad++… probably because I tend to do commits on a per-project or at least per-directory basis, rather than on a per-file basis.

By this, I meant to say that I, personally, probably wouldn’t end up adding such a plugin to my workflow, even if I knew the SCC API.

That said, even without a dedicated plugin, you aren’t without options: if you know Python or Lua or Javascript, there are scripting plugins available for Notepad++, which allow you to write code in your favorite interpreted language that have all the same hooks that true compiled plugin DLLs have. So if you know a scripting language and know how to access the SCC API, it shouldn’t be too difficult to get plugin-like behavior from one or more such scripts.

I had first come across the old CVS version control software in the '90s during an internship (though at that point, I barely understood what it was meant to do), and started using Subversion in the '00s at work, and I tangentially touch Git since the late '10s (I usually use github’s svn-access bridge rather than actually using git, so I can keep to my learned-at-work svn workflow for my home/freetime projects as well). In all that time of version control, I had never come across “SCC API”, so I had to Google it. (That’s not to say it wasn’t common in some necks of the woods; I had just never run across the term.)

The first hit had nothing to do with version control. The next two were claiming obsolete and legacy. I didn’t read details on those, though I do see a few more hits down (below my screenshot) from 2016 that mentions Visual Studio has a SCC API access… so I guess it’s not completely unheard of.

But my ignorance of SCC API aside: as with any other plugin for Notepad++: it takes someone who has the skillset to write a plugin and who has the interest/need for the functions to be implemented in order to get a plugin written. It may be that someone in some obscure corner of the internet, or someone internal to some workplace, has written such a plugin… but not all plugins that are written are made public, and even the ones that are public may not be easily-findable or submitted to the Plugins Admin plugin list.

Personally, even though I’ve added NppExec scripts that can add and commit files to my SVN repos, I find that the vast majority of my SVN-ing occurs in Windows Explorer TortoiseSVN extensions or the command line, rather than inside Notepad++… probably because I tend to do commits on a per-project or at least per-directory basis, rather than on a per-file basis.