2057816 - FileLink doesn't show service_icon in message draft

Status: UNCONFIRMED

(Thunderbird :: FileLink, defect)

Description

[Johannes Endres]

Attachment: Older versions (left) show the service_icon, newer versions (right) don't

Steps to reproduce:

1. I made a FileLink Add-on that returns an external https URL as the service_icon in the CloudFileTemplateInfo from the onFileUpload handler. (See branch https://gitlab.com/joendres/failing-filelink/-/tree/favicon-not-loading for an example)
2. I added a link to a draft message using this FileLink provider.

Actual results:

The icon didn't appear in the message draft.

This is reproducible with Thunderbird version 135.0b1 and newer.

Expected results:

The icon should have appeared in the draft message, because the sending user should see what the receiving user will see.

This is the behaviour in Thunderbird versions from 96.0 (that introduced the service_icon property) up to 134.0.