glibc is considering adding SHT_RELR/DT_RELR support:
ld.so: Support DT_RELR relative relocation format
eu-readelf -r needs to print these relocations, too.
I have some trouble locating the definite/canonical definition of RELR. Do you happen to have a pointer to the agreed upon spec?
There is no official wording yet. The generic-abi thread is all we have at the moment: https://groups.google.com/g/generic-abi/c/bX460iggiKg
Sorry. Maybe I was a bit too proactive in filing this.