HEAD Examiner от Boian Berberov

This add-on scans each page (its HEAD), extracts metadata, and forwards it to other extensions, which provide an actionable user interface based on the metadata. This way, each page is scanned only once, for multiple extensions, instead of once, by each extension.

It currently works with the following extensions:

• Table of Contents Button
• First Page Button
• Previous Page Button
• Next Page Button
• Last Page Button
• Index Button

Planned future extensions support:

• Feed (RSS) Indicator
• Twitter/X Card Preview

You can also log the output from each page scan to the extension's console for debugging.