It appears the parsoid apt repo https://releases.wikimedia.org/debian/dists/jessie-mediawiki/ was updated without incrementing the Version: in the https://releases.wikimedia.org/debian/dists/jessie-mediawiki/Release file.
Anyone who updated their apt cache prior to the new parsoid 0.11.0 release will not be able to see the parsoid 0.11.0 release.
$ sudo apt update ... Hit:3 https://releases.wikimedia.org/debian jessie-mediawiki InRelease ... $ apt-cache madison parsoid parsoid | 0.10.0all | https://releases.wikimedia.org/debian jessie-mediawiki/main amd64 Packages parsoid | 0.10.0all | https://releases.wikimedia.org/debian jessie-mediawiki/main i386 Packages
Workaround:
$ sudo rm /var/lib/apt/lists/releases.wikimedia.org_debian_dists_jessie-mediawiki_InRelease $ sudo apt-get update ... Get:42 https://releases.wikimedia.org/debian jessie-mediawiki/main i386 Packages [504 B] Get:43 https://releases.wikimedia.org/debian jessie-mediawiki/main amd64 Packages [504 B] $ apt-cache madison parsoid parsoid | 0.11.0all | https://releases.wikimedia.org/debian jessie-mediawiki/main amd64 Packages parsoid | 0.11.0all | https://releases.wikimedia.org/debian jessie-mediawiki/main i386 Packages ...
Fix: Please update the apt repo with a new build and/or increment of the apt repo version.