Module
Maximum size in bytes that readText will decode. Markdown notes in the
current corpus are well under 16 KiB; 1 MiB is a generous safety cap that
still prevents accidental binary reads from being materialised as
potentially-huge strings in memory.
Rejects keys that could escape their store: empty, absolute, or containing a
.. segment.
Rejects keys whose extension is not one readText may decode.
Why a content key was refused.