I don't know what's wrong with this extension, but I install all other extensions fine, but this one has been giving me an error for a month now: "Installation aborted because the add-on appears to be corrupt."

I'm using Firefox 115.20.0 ESR (32-bit). For testing, I even disabled add-on signature verification, but it still reports that the add-on appears to be corrupt. Installing it from the downloaded XPI file doesn't work either.

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In response to the message below:
I cannot do that, as this is the latest version for Windows 7.
Furthermore, the supported versions are listed as follows:
Latest version
Version 2.8
Released Sep 2, 2026 - 90.86 KB
Works with Firefox 58.0 and later, Android 142.0 and later

In other words, it ought to work, but it doesn't.