At commit 8242c1848347ac2e56190f1588b212960caaadf0, using the "Save As" button of the log window only actually saves a file if the file extension (".txt" or ".TXT") is entered manually, although the dialog suggests a suitable extension is added automatically (at least that's what every software I can think of that shows a file extension in a "Save As" dialog does). This is the case even if you enter the name of an already existing file and confirm that you want to overwrite it!