version not detected, but possibly could be

[k4lizen]

pwn_efficient_todo.zip

~> pwninit --bin todo
bin: todo
libc: ./libc.so.6
ld: ./ld-linux-x86-64.so.2

warning: failed detecting libc version (is the libc an Ubuntu glibc?): failed finding version string
copying todo to todo_patched
running patchelf on todo_patched
writing solve.py stub

~> strings libc.so.6 | grep "Lib"
GNU C Library (GNU libc) stable release version 2.35.

Usually its like GNU C Library (Ubuntu GLIBC 2.35-0ubuntu3.6) stable release version 2.35. but even without the 2.35-0ubuntu3.6 you could infer the version just from the 2.35.

[k4lizen]

Now that I think about it, the (GNU libc) probably means it was taken straight from https://ftp.gnu.org/gnu/glibc/ instead of being packaged by Ubuntu?

[tesuji]

I guess one need to add support for other distros. Currently only Ubuntu flavors are supported.
libc from fedora has the same format as stated by OP:

GNU C Library (GNU libc) stable release version 2.36.