This works well, but it's missing a few essential features:

1. An icon for the toolbar.
2. A quick ability to turn on/off.
3. Whitelisting and blacklisting modes.

With all of these, it would be a 5 star for sure.

Breaks PDF downloads in Google Docs but otherwise works well.

Since it doesn't allow to download attachments from gmail a whitelist would be nice.

Does the job, thanks – tested with the PDF reports under https://ec.europa.eu/digital-single-market/en/news/annual-self-assessment-reports-signatories-code-practice-disinformation-2019#block-views-39e10d54fad34071dca96fe7d7133f38

Four stars here.

----

Five stars to Display inline https://addons.mozilla.org/addon/display-inline/ for having a longer history and offering a support address.

Works great however it would be great if it had a text field where I could enter the websites I don't want to be mangled by this add-on.

One site, one line.

Subdomains will have to be matched too, e.g.

domain.com should also match one.domain.com and two.domain.com

A "Save" button would be nice, so that Firefox wouldn't save the contents of this field on every key press.