"Play Sound" has disappeared from Thunderbird filter actions, replaced with "Missing Custom Action".
This was an available custom filter action for specific incoming email messages until the most recent Thunderbird update to 60.3.0.
ყველა პასუხი (4)
The 'Play Sound' filter action is provided by the ToneQuilla add-on. You can install it in TB 60 if you first open Tools/Options/Advanced/General/Config. editor and double-click the preference extensions.strictCompatibility to false, OK to close Options. It installs, but may not work completely.
https://support.mozilla.org/en-US/questions/1211381
Another option is Mailbox Alert.
Downloading and then clicking on "tonequilla-1.1.1-tb+sm.xpi" does not install anything but rather opens as raw code in Wordpad or else as an attachment in a new Thunderbird email message. Windows 7.
Drag the xpi file and drop it onto Tools/Add-ons/Extensions in TB.
https://support.mozilla.org/en-US/kb/installing-addon-thunderbird
But shame on Thunderbird for subtracting out this existing option from v60 without any notice to users. Double shame again for making this fix so complex and non-intuitive.