What is the source of these ICS files?

While I know they are text files and toggling the display of attachments inline should control Thunderbird desire to display the contents. That toggling the inline display does not would indicate the email is itself damaged or malformed.

Even if there is a garbled mess in the email body in a correctly formed email there should still be an ics attachment to be manipulated as any other file.

BTW what is the superior calendar program you are using?

Anything at all. I don't think I've ever seen an ICS file attachment in Thunderbird. If I open the same email in another program it's there.

If it matters (it doesn't), the calendar program I typically use is the built-in calendar app on the Mac. I never said it was superior; that's you being snide. BTW.

>Even if there is a garbled mess in the email body in a correctly formed email there should still be an ics attachment to be manipulated as any other file.

Yes, that's what I would like to see, but never have in Thunderbird.

I'm running Thunderbird 128.8.1esr (64 bits), Ubuntu 24.04.2 LTS, with the same issue.

I have already edited many configurations and installed many extensions due to the same problem. Although I see that attached ICS's sources show "Content-Type: text/html" instead of "Content-Type: text/calendar", they have always worked for me, until very recently. When I looked for older invitations, which I had accepted in the past, now they appear as part of the text instead of being a file, as they surely were (as I had accepted them).

When I forward any of these ics-related mails elsewhere, including other local e-mail clients (Evolution), they're properly rendered as files.

This hasn't been happening for more than some few weeks, as far as I can see here.

Thanks!