apt-file can not find a dkms file

Before I upgrade to Debian Bullseye, apt-file was pretty logical. Now I can't get it to work. What am I doing wrong? Did the behavior change? # apt-file update Hit:1 http://repo.steampowered.com/steam precise InRelease Hit:2 https://updates.signal.org/desktop/apt xenial InRelease Hit:3 http://security.debian.org/debian-security bullseye-security InRelease Hit:4 http://deb.debian.org/debian bullseye InRelease Hit:5 https://packages.riot.im/debian default InRelease Reading package lists... Done Building dependency tree Reading state information... Done 9 packages can be upgraded. Run 'apt list --upgradable' to see them. Prove the file is there... # locate v4l2loopback.ko /usr/lib/modules/5.6.0-1-amd64/updates/dkms/v4l2loopback.ko /var/lib/dkms/v4l2loopback/0.12.5/5.6.0-1-amd64/x86_64/module/v4l2loopback.ko apt-file can't tell me what package provides it: # apt-file search v4l2loopback.ko ... nothing... What package provides v4l2loopback.ko? How can I find it out? Did the behavior of apt-file change? ------- Dpkg also can't find it. # dpkg -S /usr/lib/modules/5.6.0-1-amd64/updates/dkms/v4l2loopback.ko dpkg-query: no path found matching pattern /usr/lib/modules/5.6.0-1-amd64/updates/dkms/v4l2loopback.ko