What Characters are allowed in Plugin Names?

I’d like to have my artist coworkers put a tag in the name of their meshes (in 3dsMax) so I can lookup specific meshes by said tag.
I have noticed most characters other then letters and numbers, get converted to underscores ‘_’.

Are there any other characters I could use that won’t get converted to underscores?
it would be usefull to me, because then I could tell my coworkers to exclusively use that character for tags.

I’m curious for your thoughts!
and thanks for reading!

P.s. I just realised i should have probably posted this in general instead; Apologies!

Here is the code that checks plugin name validity in V-Ray AppSDK:

bool checkPluginNameValidity(const char* name) {
    if (!name || !*name)
        return false;

    // A digit not allowed at first character position
    if (*name >= '0' && *name <= '9')
        return false;

    while (char c = *name) {
        // Allowed characters: A-Z a-z 0-9 @ | _
        if ((c < '0' || c > '9') && (c < 'A' || c > 'Z') && (c < 'a' || c > 'z') && c != '@' && c != '|' && c != '_')
            return false;
        ++name;
    }
    return true;
}
​

Thanks! Thats perfect! Exactly what I needed to know.

The ‘|’ character does in fact stay ‘|’ when I save a maxscene to a .VRScene so I could use this for tags like so:
item_1|TAG| => item_1|TAG|@node_1234

Outside of artist not correctly naming meshes, is there any false positives i should be aware of?
I don’t think I have seen the ‘|’ character in any plugin names so far.

I think I’ve seen | in vrscenes exported from some V-Ray integrations, SketchUp maybe.