Steps to reproduce:
- Go to Special:Preferences>Search page
- Observe the font size of the descriptive text for an option such as the font size of the text "Corrects up to two typos. Resolves close redirects." for Default (Recommended) option
- Compare this font size with the font size of the text "Collects performance-related information for the current page and exposes it via a sidebar link. Only available in the main namespace." for the option Enable Performance inspector under the Special:Preferences>Editing tab
The font size observed on step 2 should be the same as the other one on step 3.