EDIT: Looking into it, seems the tab memory viewer is only looking at the page and does not take extensions into account; if the extensions inject JS/Style to the page then it counts, and Bitwarden seems to only add a small amount of JS to find password dialogues. It uses memory, but outside of the tab viewer.
Only bitwarden (no ad-blockers or anything).
https://sh.drk.sc/~dijit/hn_tab_extensions.png
EDIT: Looking into it, seems the tab memory viewer is only looking at the page and does not take extensions into account; if the extensions inject JS/Style to the page then it counts, and Bitwarden seems to only add a small amount of JS to find password dialogues. It uses memory, but outside of the tab viewer.