Looking at https://test.wikipedia.org/wiki/Thesaurus?uselang=test where the LastModified extension has recently been enabled, the little icons used on wikis such as the English Wikipedia overlap with the extension's output. I'll attach a screenshot momentarily.
Ideally this extension's output would be above the article tabs (where there's plenty of room). Putting this text on the same line as the article title risks hitting the little icons or, with long page titles, hitting the page title. This is bad.
Version: unspecified
Severity: normal