[xjtu-ctgg]

Fixes #20473

The standard viewer's save button uses the localized pdfjs-save-button message, but that message only exposed a tooltip through .title. Add a localized .aria-label so screen reader users receive an accessible name.

The integration test checks the rendered #downloadButton in the viewer and verifies its aria-label.

Tests: node --check test/integration/viewer_spec.mjs (full PDF.js integration tests require the repository dependencies and browser test setup).

[flodolo]

This type of change requires a new ID
https://mozilla-l10n.github.io/documentation/localization/making_string_changes.html

[xjtu-ctgg]

Addressed the localization review: kept pdfjs-save-button unchanged, added the new pdfjs-save-button-with-aria-label ID, and switched the standard viewer button to use it.

[Snuffleupagus]

Sorry, but setting aria-label on just a single button like this seems strange/wrong since you'd expect that other buttons are similarly affected!?
I've tagged the issue with requires-feedback-from-ux-ui, since this seems like something that'd benefit from that before making any changes here (and the patch looks wrong in how it leaves the old l10n-id).