Because it’s fully client-side JavaScript, Eaglercraft 121 does not:
However, be cautious: Some unblocked sites inject ads or trackers. Stick to trusted mirrors or download the official offline HTML file from GitHub (then host it locally or on a USB drive). The “121” version is generally safe, but always use an ad blocker. eaglercraft unblocked 121
"Unblocked" means the HTML file has been stripped of any links to banned domains. Most schools block GitHub and GitLab. An "Unblocked 121" version is typically hosted on obscure, encrypted, or Google Sites domains that IT departments rarely flag. However, be cautious : Some unblocked sites inject