The bottom layer every HTML reader in the Craft apps carried its own copy
of. The tokenizer is MailCraft's (crates/html/src/tokenizer.rs), with what
it dropped and capped turned into Options and Limits, a self-closing flag,
and raw_content for callers that read a style sheet's text. The character
references are WordCraft's (crates/formats/src/html/entity.rs at 06c2ae6f):
its name table and the 94 legacy names that decode without a semicolon,
with MailCraft's Latin-1 and Greek tables and its handling of numbers too
long to be numbers.
No tree, no CSS, no decoding of bytes.