So just a few ideas...
Testing the check, I would load an addon and compose checks for its strings, begining with the name, something it says to the player when loaded, and up to anything it reports to the player's chat. Considering reference to the FrameScript::GetText client function (and hoping we got the offset correctly), it probably checks addon output strings. Also, the "failure" of the check may be the desired result, while "ok" may mean "the string is found".
Once again, ensure that your client is of 5875 build. The in-core warden isn't ready for any other version for now.
Well, FYI the present code was ported from the TC one. The TC table contains no entries for this type of check, and probably for a reason.
I suspect this check type to be usable for addon activity. Yeah, there is the way to ban an addon through respective DB table. This check must be for monitoring some addons that aren't banned (yet).
I'm experimenting with Warden on a local Mangos Zero install, trying to figure out how Warden's LUA_STR_CHECK works. No matter what value I use for "str", the check seems to fail. Here's an example:
I'm connecting to the server with just a normal unmodified client.
Does anybody know how this Warden check works? What does it actually do on the client side? And how is it normally used?