Improve definition of frontend component

Co-authored-by: Rosio <[email protected]>

Author: mfisher87

03-vocabulary.md

@@ -20,8 +20,8 @@ running on, for example to read files from disk.
 [See the official docs for more!](https://jupyter-server.readthedocs.io/en/stable/developers/extensions.html)
 
 Frontend extension
-: An extension which adds functionality that executes solely in the browser and interact
-with existing JupyterLab frontend components.
+: An extension which modifies the user interface and/or adds functionality that executes
+solely in the browser, and interacts with existing JupyterLab frontend components.
 This includes themes, UI elements, viewers, code editors, and more.
 They are built with [Lumino](https://lumino.readthedocs.io/en/latest/) and/or
 [React](https://react.dev/learn) components.