Remove This Application Was Created By A Google Apps Script User -

These do not remove the banner for other users but can hide it on your own browser:

For more complex applications, you might consider publishing your script as an (for Docs, Sheets, Slides, or Forms) or a Google Workspace add-on (for Gmail, Calendar, Drive, etc.). Publishing an add-on requires verification and a review by Google before it can be listed on the Google Workspace Marketplace. This is the ultimate sign of trust and legitimacy. The process is similar to the OAuth verification but includes additional steps for a full Marketplace listing. Once your add-on is published, the warning is entirely removed for all users. These do not remove the banner for other

No. The warning is purely informational. Your script continues to run perfectly. Users can click through and use the app normally. However: The process is similar to the OAuth verification

This only works if every user is in the same Google Workspace domain as the developer. External users will still see the full warning. The warning is purely informational

Steps taken (brief, numbered): list exact actions so others can reproduce. Example: