These tests, and their [accompanying Wiki page](https://github.com/mozilla/pdf.js/wiki/Required-Browser-Features), haven't received any real updates for *many years* and are sufficiently out of date to be effectively useless now.
Providing *irrelevant* compatibility information seems overall worse than not providing any information, and as suggested in the issue it'd probably be better to use https://github.com/mozilla/pdf.js#online-demo for checking if a particular platform/browser is supported.
Thanks to version control, it's easy to restore these files should the need ever arise. However, re-introducing these tests would essentially require updating every single test-case *and* a commitment to keeping them up to date with future code changes.
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