The file is bit-exact reference material and worth keeping dense, but it used "gloom" thirty times without ever saying it is a bloom filter library, never said which upstream it tracks, and never said why bit-exactness matters rather than mere compatibility. A reader arriving cold has no entry point. Adds a short orientation block -- what jss, gloom and upstream are, and the reason the constants are copied verbatim: a bloom filter promises no false negatives, so a single misplaced bit makes a reader skip a segment that does hold the DID, and nothing in the format detects it. The spec content is unchanged. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>