Comment 50 for bug 1509139

Chad, I don't agree that "the XDG utilities aren't written very well." The problem is that there's little agreement between both applications and platforms on how defaults are detected, and the script is doing its best to accommodate all the scenarios that cause issues. I believe I have tried EVERY fix (short of installing testing versions from PPAs of XDG-utils and Chromium) and Chromium STILL doesn't know that it's the default browser.

~$ apt-cache policy xdg-utils; grep http ~/.config/mimeapps.list ~/.local/share/applications/mimeapps.list
xdg-utils:
  Installed: 1.1.0~rc1+git20111210-7.4
  Candidate: 1.1.0~rc1+git20111210-7.4
  Version table:
 *** 1.1.0~rc1+git20111210-7.4 0
        500 http://httpredir.debian.org/debian/ jessie/main amd64 Packages
        100 /var/lib/dpkg/status
/home/USERNAME/.local/share/applications/mimeapps.list:x-scheme-handler/http=chromium.desktop
/home/USERNAME/.local/share/applications/mimeapps.list:x-scheme-handler/https=chromium.desktop

~$ uname -a
Linux debian 3.16.0-4-amd64 #1 SMP Debian 3.16.43-2 (2017-04-30) x86_64 GNU/Linux

~$ lsb_release -d
Description: Debian GNU/Linux 8.8 (jessie)

~$ apt-cache policy chromium
chromium:
  Installed: 57.0.2987.98-1~deb8u1
  Candidate: 57.0.2987.98-1~deb8u1
  Version table:
 *** 57.0.2987.98-1~deb8u1 0
        500 http://httpredir.debian.org/debian/ jessie/main amd64 Packages
        500 http://security.debian.org/ jessie/updates/main amd64 Packages
        100 /var/lib/dpkg/status

/usr/bin/xdg-settings:
198# command="`grep -E "^Exec(\[[^]=]*])?=" "$file" | cut -d= -f 2- | first_word`"
199 command="`grep -E "^Exec(\[[^]=]*])?=" "$file" | cut -d= -f 2- | first_word | head -n 1`"
200# command="`grep -E "^Exec(\[[^]=]*])?=" "$file" | cut -d= -f 2- | sed -e 's/ .*$//' | head -n 1`"

Each line uncommented in turn with no change in chrome://settings: "Chromium is not currently your default browser."