flask-wtf is a source package. python-flaskext.wtf is a binary package - a single source package can build one or more binary packages. Binary packages are wh

flask-wtf is a source package. python-flaskext.wtf is a binary package - a single source package can build one or more binary packages. Binary packages are what's found by apt-cache search and installed by apt-get install. You can install a Debian source package using: apt-get source flask-wtf (This just downloads and unpacks it into your current directory, so you don't have to be root - it's not actually modifying the installed package database). Information on the source package is available here: https://packages.debian.org/source/sid/flask-wtf https://packages.debian.org/source/sid/flask-wtf