1790187 - Migrate appstrings.properties to Fluent & format its messages from aboutNetError.mjs

Status: NEW

(Firefox :: Security, task)

Description

[Eemeli Aro [:eemeli]]

Currently, the messages from appstrings.properties (dom, browser) are formatted by nsDocShell::DisplayLoadError(), which passes the formatted message to the about:neterror/about:certerror page as a query parameter.

It would be better if this formatting was done closer to the front-end, based on an error identifier. Using Fluent for this also allows much easier use of { -brand-short-name }, which should let the overridden dom version of the file be dropped, and the browser's messages be used for all users (currently desktop browsers and Thunderbird).

Some of the error messages are parameterised. Where the information may be determined from the JS side, that should be done rather than also passing their values as additional query parameters.