Deblobbing is the attempt to remove some of the binary blobs shipped with linux distro source code libraries.

"blobs are binary firmware,"

Uhhh... no. If a distro has firmware, something is already way wrong. Consider the HLDS - GHA2N - HH SATA DVD+/-RW DVD player. A new firmware for it was uploaded in 2013, version A103, A01. It does the following:
1. To improve of write quality ( Write strategy )
a) DVD+R DL Verbatim 8x under high temp
b) DVD-R DL MKM 8x under low temp
2. To Improve of CD-ROM readability during reliability test under high temp by adjusting tilt

That's firmware. It doesn't even run on your own cpu or OS.

All "install and run" linux distros are loaded with these binary blobs. If your system does what you want, you'd know. But, if it does something you didn't want, how do you know? What if it's exfiltrating your junk? There's almost no way to know unless you review the source code, which you cannot do unless your system was deblobbed ... in which case it probably won't run.

An example of what is removed by deblob-6.8 is the enumeration of BPF preload sources/headers: kernel/bpf/preload/iterators/iterators.bpf.c, kernel/bpf/preload/iterators/iterators.lskel-little-endian.h, and kernel/bpf/preload/iterators/iterators.lskel-big-endian.h. The sed script removes embedded eBPF programs (“light skeleton”) pinned in bpffs for debugging/introspection. It's kernel infrastructure, not device drivers. Not firmware, either. Lot's of drivers are binary blobs. There are some deblobbing scripts. They are likely to make compilation fail, but the goal is to make it not fail.

The blobs aren't firmware though.