This tag is used for the questions related to the column formatting using JSON in SharePoint Online, SharePoint 2019, etc.
About column formatting:
Improve the display of columns in SharePoint lists with formatting. The column-formatting text describes the elements that are displayed and their display style. The data in the column doesn't change.
Anyone who can create and manage views in a list can access column formatting from the column settings.
You can read more about Column formatting in below articles: