If the Steam Store app/sub doesn't exist, is removed or is region-locked, redirect to steamdb.info instead of store.steampowered.com.
< Feedback on Steam Store - Removed App/Sub Redirect To SteamDB
Yes, I know, but there is no way to avoid this without disabling the functioning for middle-clicking. I could use a trick that when middle click: opens steam store or steamdb, closes the current page (the referrer) and opens the page (the referrer) again in a new tab. But this can lead to unexpected behavior and damages, like unsaved process on webpage lost. So I rather not do this.
Works, but a bug affects non-removed apps.
When middle-clicking on a store page link like this from any website, it opens and focuses on a new tab; the tab doesn't focus when the script is disabled, which is expected from middle-clicking any other link.
It sometimes opens two new tabs, but I can't reliably reproduce this.