How to determine quota(1) block size?

Google has parsed [this Duke University IT knowledgebase article](https://www.cs.duke.edu/csl/faqs/quotas_about) into an infocard alleging to _anyone_ searching "linux quota block size" that > A block quota is the limit on the actual amount of disk space that can be used by an account. This space is measured in 1 KB blocks (1 KB = 1024 bytes or characters). A quick search on this site yielded [this answer](https://unix.stackexchange.com/a/232219/26420) referring to *other* definitions of "block size", including EXT4's: > A typical block size is 4KiB. I poked around in [these source files](https://kernel.googlesource.com/pub/scm/utils/quota/quota-tools/+/refs/tags/v4.04) a bit, but their code is so sparsely commented that I was unable to grok it. I still vaguely **assume** that quota(1) reports "block size" in the associated filesystem's specific block (size rather than a universal constant like 1KiB), but how could I **verify** this? Where is the point of contact between the quota tooling codebase and the filesystem driver codebase?