There are at least two standards of Executable and Linkable Format (ELF), one of them
- System V Application Binary Interface AMD64 Architecture Processor Supplement (With LP64 and ILP32 Programming Models) Version 1.0
- Tool Interface Standard (TIS) Executable and Linking Format (ELF) Specification Version 1.2
The older one, the TIS ELF Standard 1.2 is 106 pages while the SysV ABI is 157 pages but covers ELF only on pages 63-86 (23 pages).
How do these two standards relate to each other? And which one does Linux and GNU Linker use? What is the Tool Interface Standard?