Download of MeetingBar 4.5 for Mac was available from the developer's website when we last checked. We cannot confirm if there is a free download of this app available. The actual developer of this free Mac application is Andrii Leitsius. The application is included in Productivity Tools. We recommend checking the downloaded files with any free antivirus.
From the developer:
MeetingBar shows your events list and details in the status bar and allows you to create and join meetings with one click. The app doesn't collect any data or personal information. It is entirely free and powered by an open-source community. It integrates with the Calendar app and supports all the built-in calendar providers: Google, Exchange, Office 365, Yahoo, AOL, and iCloud.
You may want to check out more Mac applications, such as MenuCalendarClock Entourage, Chronos or iCal Reply Checker, which might be similar to MeetingBar.