I can confirm the bug on 16.04, but it's only nautilus/GTK reporting the file type is "Amiga SoundTracker audio (audio/x-mod)".
In a shell it is correctly identified as text: $ file Untitled\ Document\ 1 Untitled Document 1: ASCII text Furthermore, the bug does not seem to exist any more in Ubuntu 18.10. ** Package changed: gedit (Ubuntu) => gtk+3.0 (Ubuntu) ** Changed in: gtk+3.0 (Ubuntu) Status: New => Fix Released ** Also affects: glib2.0 (Ubuntu) Importance: Undecided Status: New ** Changed in: glib2.0 (Ubuntu) Status: New => Fix Released -- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to gtk+3.0 in Ubuntu. https://bugs.launchpad.net/bugs/1778962 Title: when entering the line of text "if network manager is crashing you can restart it with sudo systemctl restart network-manager;" the editers saves the file as a Amiga SoundTracker audio (audio/x-mod) file. Status in glib2.0 package in Ubuntu: Fix Released Status in gtk+3.0 package in Ubuntu: Fix Released Bug description: when entering the line of text "if network manager is crashing you can restart it with sudo systemctl restart network-manager;" the editers saves the file as a Amiga SoundTracker audio (audio/x-mod) file. ProblemType: Bug DistroRelease: Ubuntu 16.04 Package: gedit 3.18.3-0ubuntu4 ProcVersionSignature: Ubuntu 4.13.0-45.50~16.04.1-generic 4.13.16 Uname: Linux 4.13.0-45-generic x86_64 ApportVersion: 2.20.1-0ubuntu2.18 Architecture: amd64 CurrentDesktop: Unity Date: Wed Jun 27 13:32:25 2018 InstallationDate: Installed on 2018-02-20 (126 days ago) InstallationMedia: Ubuntu 16.04.3 LTS "Xenial Xerus" - Release amd64 (20170801) SourcePackage: gedit UpgradeStatus: No upgrade log present (probably fresh install) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/glib2.0/+bug/1778962/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : touch-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp