Preferably open source.
Somethimg that can open a XML file and slow the elements to be edited but without the danger of a txt editor where clumsy people can edit a tag ruining the file.
i use notepad++, doesn't stop tag editing but its syntax highlighting is good and it will check and highlight errors.
Was goign to suggest Notepad++ but for the protecting parts of it section, I'd be looking at pairing it with something to do differential stuff to keep a record of what the changes were - or useful answer why are you letting clumsy people near stuff that you don't want changed? Can you not find a better way to expose the bits you want to be editable?
I want a quick solution for people on site to be able to edit the config files. It more about limiting the potential for errors rather than eliminating. I could write a config tool but thought there must be something like this already in existence... Plus time is a issue.
Firstobject Foxe can be useful. You can set it to just show the 'tree view', maybe less likely to mes things up than the full text.
Microsoft XML Notepad?
Free and XML specific.
Visual Studio Code is pretty neat
Some good ideas. I will now have to fight it to get them downloaded to test.
If not I will have to write something.
If not I will have to write something.
Probably best just to write something then you can sense check what they enter as well. It isn't just a case of messing the tags, they could also enter something that breaks something
...says someone that once put a hole in a block of aluminium by missing off a zero 🙁

