Thunderbird moved it's settings from a dedicated window to a tab in Thunderbird 68. Along with this change came a search box that was to replace the well defined layout that made describing the location of setting fairly simple.
I am increasingly getting the feeling that people are not using this search option and continue to plow through the options looking for what they want. This can be helpful if you have no idea what you think will be used as a term to describe what you are looking for, or to familiarise yourself with what options appear to be available. But when you are looking for things you know the names of it is a very slow way to do things. I must emphasise that this is a setting search, not a help search.
One instance is the Thunderbird config editor. There is a button for this right at the bottom of the general tab, I know this and can tell you. But that is a long list under "general" to scroll through
Using the search option, which refines the search on every key stroke is a faster method. The following image is what is displayed when type CO in the search box
Then we have the same list following the typing of config
and finally typing the complete term config editor
All three of these searches, as well as the option of scrolling, would all eventually get you to the config editor button. Personally, I think typing the whole thing makes it easiest, but it is whatever souit you.
This search really comes into it's own on searches like PDF which does not return a "result" as such but displays only the list box for "content type" actions. The list has an action for PDF content.
Another good demonstration of it's ability to find setting is to type "file". This returns a number of "secondary" results where the search term is in a list that is not visible, like the list of actions for content types.
This does not help when you type things that you expect to have results and don't like attachments, so sometime the old plow through is the only way to find something. But I do recommend the use of searching to get where you are going, until it lets you down.