Is Merge duplicate Google Calendar events into one rainbow safe?

This extension combines duplicate Google Calendar events into one color-blended entry.

It reduces clutter when shared calendars or multiple invited email addresses show the same event more than once. It also adds blue weekend backgrounds in Google Calendar views, including the new event box and mini calendar, and is tuned for dark mode and Dark Reader. The description says it works only in the browser, does not modify events, shows no ads, and does not send user data anywhere.