Given the possibility of defining multiple rulers (vertical lines), I think it might be nice to give those rulers a label/name/description, that is displayed e.g. at the top of the ruler. This can be useful for new project members to quickly understand what ruler to follow.

For example PEP 8 specifies:

Limit all lines to a maximum of 79 characters.

For flowing long blocks of text with fewer structural restrictions (docstrings or comments), the line length should be limited to 72 characters.

Thus, I have at least two rulers for working on projects that follow PEP 8. New project members might be confused why there are two different rulers defining the maximum code with. It would be helpful to have a small label at the top of the ruler like docstring and code.

Furthermore, for me personally, I have rulers activated by default for 72, 79, 80,and 88 if the project itself doesn't specify otherwise. And more often then not I might get confused. Even just putting the actual width next to the ruler would help.