Afaik, LGPL means that the library has to remain dynamically linked. That’s it. No static linking is allowed and no embedding (i.e. hardcoding) is allowed unless also the outer project is also in a LGPL-compatible license.

So, no, they wouldn’t be legally allowed to steal your source by hardcoding it, if that’s what you are worried about.

The issue is with code and resources that cannot be dynamically linked. I called them “glue code”, that’s the stuff developers need, in order to use your library. That is not directly your library, but you will be shipping it with your library, most likely. You will need a different license for those resources, maybe MIT or even a public domain license such as CC0.

EDIT: I noticed you mentioned Steamworks SDK in another comment. I know Steam provides an optional DRM solution which wraps games in their own proprietary system. That might be forbidden by LGPL, I’m not sure. But linking an LGPL library to the same game that links to the proprietary Steamworks SDK shouldn’t be a problem, as long as the linking is dynamic and not static.

Why not LGPL the Rust code, and CC0 the glue code?