The start page appeal to donate can’t currently be turned off. If you like, you can change the start page to something else. To do this, in Thunderbird go to Options | General
目前暂时无法关闭起始页面上的募捐广告。如果需要，您可以考虑更改起始页面，具体选项在 Thunderbird 中的“选项”->"常规设置"。