There are a couple of bare references to "size_t" in the standard, not inside a "namespace std" block, that should probably instead be std::size_t to be consistent with the majority of references (which either use "std::size_t" or are describing functions that are defined within namespace std). E.g.,

• [lex.ext]p7 has an example for "std::string operator "" _w(const char16_t*, size_t);"; std::string here is fully qualified, so size_t should probably be too.
• "Table 26 -- Hash requirements [hash]" in [allocator.requirements] mentions "size_t" twice in the "Return type" column (and also "numeric_limits" once in the Requirement column); since allocators aren't necessarily in the 'std' namespace, these references should probably be fully qualified.
• "Table 115 -- Seed sequence requirements" in [rand.req.seedseq] mentions "size_t" in the "Return type" column; again, seed sequences don't need to be declared in the 'std' namespace, so I think this should be std::size_t.