Here is the article on how to install Firefox on a Mac. https://support.mozilla.org/en-US/kb/how-download-and-install-firefox-mac

Why the old Firefox 72.0.2 version?

If this is about using Firefox on macOS.

For macOS 10.9, 10.10, 10.11 the most current you can run is Firefox 78.15.0esr https://support.mozilla.org/en-US/kb/firefox-mac-osx-users-esr

For macOS 10.12, 10.11, 10.14 the most current Firefox you can run is Firefox 115 ESR currently at 115.14.0esr. https://support.mozilla.org/en-US/kb/firefox-users-macos-1012-1013-1014-moving-to-extended-support

For Firefox 116.0 or later you need macOS 10.15 or later to run.

Note that 72.0.2 is a so called watershed version that has migration code to prevent issues with password when updating to 73+

• 1607798 - Add a new watershed for Firefox 72.0.2 and update some existing ones to avoid password migration issues when updating to 73+