I can confirm the behavior for a local address book. Adding a http:// prefix by default to the domain name does not sound like a good idea to me though, as most web sites use https these days. Unfortunately there seems to be more to this, and it's worse. I do use a CardDAV address book for Google Contacts. When attempting to create a new contact with a website field (e.g. thunderbird.net) it fails miserably. - adding just thunderbird.net - contact cannot be saved - adding http://thunderbird.net - contact can be saved, but is not shown afterwards. It does sync to the server though. - editing to https://thunderbird.net - contact cannot be saved - editing the synced contact on the server to https://thunderbird.net. After syncing again, the TB address book still doesn't show the website information. When trying to edit the contact locally the website field shows https\://thunderbird.net - see screenshot.
Bug 1772488 Comment 4 Edit History
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I can confirm the behavior described above for a local address book. Adding a http:// prefix by default to the domain name does not sound like a good idea to me though, as most web sites use https these days. Unfortunately there seems to be more to this, and it's worse. I do use a CardDAV address book for Google Contacts. When attempting to create a new contact with a website field (e.g. thunderbird.net) it fails miserably. - adding just thunderbird.net - contact cannot be saved - adding http://thunderbird.net - contact can be saved, but is not shown afterwards. It does sync to the server though. - editing to https://thunderbird.net - contact cannot be saved - editing the synced contact on the server to https://thunderbird.net. After syncing again, the TB address book still doesn't show the website information. When trying to edit the contact locally the website field shows https\://thunderbird.net - see screenshot.
I can confirm the behavior described above for a local address book. Adding a http:// prefix by default to the domain name does not sound like a good idea to me though, as most web sites use https these days. Unfortunately there seems to be more to this, and it's worse. I do use a CardDAV address book for Google Contacts. When attempting to create a new contact with a website field (e.g. thunderbird.net) it fails miserably. - adding just thunderbird.net - contact cannot be saved - adding http://thunderbird.net - contact can be saved, but is not shown afterwards. It does sync to the server though. - editing to https://thunderbird.net - contact cannot be saved - editing the synced contact on the server to https://thunderbird.net. After syncing again, the TB address book still doesn't show the website information. When trying to edit the contact locally the website field shows <https\://thunderbird.net> - see screenshot.
I can confirm the behavior described above for a local address book. Adding a http:// prefix by default to the domain name does not sound like a good idea to me though, as most web sites use https these days. Unfortunately there seems to be more to this, and it's worse. I do use a CardDAV address book for Google Contacts. When attempting to create a new contact with a website field (e.g. thunderbird.net) it fails miserably. - adding just thunderbird.net - contact cannot be saved - adding http://thunderbird.net - contact can be saved, but is not shown afterwards. It does sync to the server though. - editing to https://thunderbird.net - contact cannot be saved - editing the synced contact on the server to https://thunderbird.net. After syncing again, the TB address book still doesn't show the website information. When trying to edit the contact locally the website field shows a crippled URL - see screenshot.