Summary

Any of our webworker protection breaks Anubis https://github.com/TecharoHQ/anubis (a proof-of-work challenge in order to protect upstream resources from scraper bots).

Setup

Pages affected, for example, https://anubis.techaro.lol, https://gnome.pages.gitlab.gnome.org/atk/, https://source.puri.sm/Librem5/3D_designs, see also https://discourse.gnome.org/t/difficulty-accessing-gitlab-through-proof-of-work-anubis/27924

1. Navigate to https://gnome.pages.gitlab.gnome.org/atk/
2. You should see "Failed to calculate challenge: undefined", "Failed to calculate challenge: Worker is not a constructor" or "Failed to calculate challenge: Permission denied to access object" depending on the WebWorker protection settings.

Expected result

JShelter is compatible with anubis

Actual result

JShelter breaks pages with anubis

Reproducibility

Once, I was able to get through anubis but I am not sure why.

Have you tried other steps to solve the issue?

1. I opened https://github.com/TecharoHQ/anubis/issues/399
2. I opened https://github.com/TecharoHQ/anubis/issues/400

Additional information / notes

This issue is caused by the broken Worker protection, see #80