My email service-provider here in Australia is Telstra. This service can be accessed either from Telstra's Webmail site via a browser or via an email client app. I've recently linked Thunderbird 78 to the service, using the IMAP option. One of the filter options offered by Thunderbird provides for the automatic deletion of an incoming email if it has certain words included in the subject heading. I have found that this filter can be bypassed by the simple trick of including one or more emojis in the subject heading. Scammers appear to be aware of this dodge, because some types of phishing emails I've been getting have subject heading which always start with the same words but also include a number of emojis, which like the sender's addresses, differ from one case to the next. I suppose that if I repeatedly tag such phishing emails as spam, Thunderbird will eventually learn to shunt them straight into the junk folder. Nevertheless, the issue I've described does seem to represent a loophole in the app's defenses, and which ought to receive attention. I lack the technical expertise to judge whether this issue should be regarded as a bug in Thunderbird, or whether it perhaps has arisen just with the particular service-provider. I mention this latter possibility because the setting options on Telstra's Webmail site also include provision for the same type of inbox-management rule, and it too is fooled by the emoji trick. Any helpful comments or feedback would be appreciated.