webextension--bootstrap-responsiveHelper Show the bootstrap grid class currently active (XS, SM, MD, LG, XL). Demo Install Firefox https://addons.mozilla.org/en-US/firefox/addon/bootstrap-responsive-helper/ Bootstrap Compatibility Version Result 5.0.0 ✔️ 4.0.0 ✔️ 4 Beta ✔️ 4 Alpha 6 ✔️ 4 Alpha 2 🚫 3.3.x ✔️