What are the blue brackets?

With one of the last LO versions some ligth blue brackets ("[", “]”) have appeared in writer, I cannot fine any explication of what are they…

Bookmarks can be displayed in line with text, see release notes for version 7. [Edit changed bookmark link to #Writer]

Settings in Tools > Options > LibreOffice Writer > Formatting Aids > Bookmarks. Cheers, Al

Actually the blue brackets I see don’t seem to deal with bookmarks, they surround blocks of text. The release notes you are linking don’t speak of blue brackets

Please post anonymised sample then. Cheers, Al

ok, actually unsetting Tools > Options > LibreOffice Writer > Formatting Aids > Bookmarks the brackets desappeared. But the weird thing is that the navigaor pane on the right isn’t available… Why?

Click View > Sidebar (Ctrl+F5 , might have to do twice for it to appear), then click on compass icon (tooltip Navigator).

I suggest downloading and using the Writer Guide for reference. Cheers, Al

BTW if my answer is correct, please click the tick mark beside it to turn it from grey to green in case someone else is looking for similar solution.