From the build 2022.2 b21531 onwards the users will be able to show banner within the project list page.
To add banner to your project list page, simply go to the folder on the file system and create banner.md file in the folder. The content of the file can be expressed as Markdown, which is a powerful yet easy to learn markup language. For more details on how to write in markdown click here.
The page visitor can click on "Do not show this again" option to hide the banner permanently (or until the banner content changes).
NOTE: Banners are folder specific and not inherited from the parent folders (unlike branding!).