Update:

As far as I know, this should be a subset of the PO format (http://pology.nedohodnik.net/doc/user/en_US/ch-poformat.html....).

The file format used by a18n is JSON, where its keys are extracted from code (using `a18n extract`) into one of these formats:

- "static text"

- "dynamic text with one variable: %s"

- "dynamic text with multiple variables: %1, %2, %3"

- "#some.text.id" or "xxx#some.text.id" -- user manually assign text an ID with: a18n("xxx", {_: "some.text.id"})

(It worth noting that my company further converts this JSON to Excel before sending to translators)