https://www.gnu.org/software/guile/manual/html_node/Hash-Table-Reference.html

The Guile manual does not formally introduce (ice-9 hash-table).

The first time it does is just by showing a code example where it uses it:

(use-modules (ice-9 hash-table))
(alist->hash-table '((foo . 1) (bar . 2)))

This is a bit of a disorienting style of documentation. I think it would be better to formally introduce the module with some background context about why it exists as a courtesy to the reader/new guile community member.