Goal of LGPL is to protect freedom of developers to modify code of a library (e.g. to improve it, fix bugs, fix incompatibilities, port to new hardware, etc.) shipped as part of proprietary application. This freedom is important for developers of niche OS'es. This protection works, because of hard consequences for proprietary code in case of license violation: proprietary code must be released under GPL then.
MPL doesn't protect such developers, but it "forces" contribution of changes back to original code. In reality, it's ignored.
Header-only library cannot be compiled as separate library, so requirements of LGPL cannot be met by proprietary code.
MPL doesn't protect such developers, but it "forces" contribution of changes back to original code. In reality, it's ignored.
Header-only library cannot be compiled as separate library, so requirements of LGPL cannot be met by proprietary code.