I may be late to the party, but I can’t find anything directly related to this, so here goes! I’ve noticed that in 184.108.40.206, the gutter is larger than in 12.6, by the width of the code folding column. I found out that there are four columns in the gutter, line number, bookmark, status-y thingy and code folding, and that in 12.6, the bookmark goes in the line number column. I’m guessing therefore that bookmarks have been split off into their own column in 12.7.
However, I’ve never used the bookmark feature, and now the line numbers seem awfully far away from the rest of the info in the gutter. Is there any chance of hiding the bookmark column until bookmarks are selected? That way, the gutter would go back to its old width, and only expand if you need it to (in the same way that the line number column automatically increases if the line number is > 99.
Ps. here’s a pic to show the difference: