Some of the features you mentioned are not really features of ELF itself but rather tacked on by tools and libraries. For instance, symbol versioning is just a

Some of the features you mentioned are not really features of ELF itself but rather tacked on by tools and libraries. For instance, symbol versioning is just an ad-hoc convention for embedding version numbers into the symbol strings themselves. And the convention assumes that the source language is C, which requires other languages to mangle their symbols to make them fit. Some features that systems rely on are not even officially documented. I've read accounts from a developer of a linker who had to read through code, blogs and old mailing lists to figure out the actual format for a feature.