EDIT: As @wimpy states in post #2. The packages are updated. I will keep this here if you experienced this issue.
Just to let you know. I used the flexiondotorg ppa to install Minecraft manually on another computer and got an error message stating that favicon.ico could not be downloaded as it had been permanently moved, resulting in a 301 error message from wget.
It appears that the Minecraft.net website got an overhaul and the icon can now be found at:
A workaround:
I thought I had a nice workaround, but I kept getting the same error message over and over again, so I had to do some hacking But it worked!
First install Minecraft using the Software Boutique and then open up a terminal (F12 for tilda wil do just fine) and do the following:
cd /var/lib/dpkg/info
sudo pluma minecraft-installer.postinst
dpkg: error processing package minecraft-installer (–configure):
subprocess installed post-installation script returned error exit status 8
Processing triggers for hicolor-icon-theme (0.15-0ubuntu1) …
Errors were encountered while processing:
minecraft-installer
E: Sub-process /usr/bin/dpkg returned an error code (1)