The 3.2 version of Tab Options for Mac is available as a free download on our website. The application lies within Internet & Network Tools, more precisely Browser extensions.
From the developer:
Tab Options (formerly Tabkeys) adds a few tab-related options to the ones built into Safari: you can control where new tabs appear on the tab bar, what happens when you close a tab, and more. Tab Options keeps track of your most recently activated tabs, so you can switch back to recently focused tabs with a key combo, or toggle between two tabs with single keystroke.
You may want to check out more software for Mac, such as SafariTabs, Tabs Plus or Tab Notes, which might be related to Tab Options.