https://bugs.winehq.org/show_bug.cgi?id=53091
--- Comment #7 from Zeb Figura z.figura12@gmail.com --- Okay, that's the clarification I was looking for—the point being you're looking for something like "can be reproduced with only Wine builtins".
I think a "builtin" keyword is potentially reasonable, but I'm not sure how much use it'll be. Existing similar keywords like "source" and "download" are meant as tools for developers—to find bugs which are easy to reproduce or investigate—but from a debugging perspective there's not much difference between a bug tagged "download,source" and a bug tagged "builtin".