My Google My Business listing has a special icon, an exclamation mark and then text between quotes underneath the opening hours. Can you tell me what is that? Below I attached the symbol with yellow color marked.”

Google calls these Justifications, but many users give other names to this feature of icons with quoted text: Info texts, Search Snippets or Mentions.
These are normally created by Google Algorithm automatically from information found in your reviews, posts, website and other online platforms (Facebook, TripAdvisor, etc).
Sometimes they are written by Google Staff for Food business related listings.
That Exclamation icon is specifically related to Google Posts, you must have posted in the past a GMB post that includes the keywords that match the query the person typed into Google.
You cannot add it manually, if you need to remove any wrong info you need to remove the culprit post or ask Google Support to remove it for you.
I hope this article helped you.
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