Files v0.1.11

Sound

• Notifications chime: a different sound for info, success, warning and
  error, at the volume you set (once, however many windows are open).
• New Settings → Sound: notification sounds (on/off, Soft / Bright / Low,
  volume, try each kind); a speaker test for headphones, 2.1, 3.1, 5.1 and
  7.1 (a tone in each speaker, a low one for the subwoofer, or all in
  turn); and the equalizer, shared with Music and song previews.

Mail

• A Details panel (the ⓘ button, or the inspector when Mail is a tab)
  shows who sent a message and how: From, Reply-To, Return-Path, the
  sender's IP and the route through servers, the mail program, SPF / DKIM /
  DMARC checks, Message-ID, the MIME type of each part, attachments, size
  and every header, all selectable.
• Quick Look on a saved message (.eml) shows it with the same details.

Music

• Yandex Music tracks start at once, streamed while they download (a grey
  bar on the seek slider shows how much has arrived); the next track of
  the queue is downloaded ahead, and played tracks stay cached.
• The inspector button opens a track panel on the right of the Music tab:
  a big cover, artist, album, length, where it comes from, and Like, Go to
  Artist, Download or Show in Files.

Tabs

• Middle-click a tab to close it, like a browser.

Installing: the builds are not signed by Apple or Microsoft yet.
macOS: open it once, then System Settings → Privacy & Security → Open Anyway.
Windows: SmartScreen → More info → Run anyway.
Linux: chmod +x the AppImage.