E: The package linux-modules-extra-5.4.0-56-generic needs to be reinstalled, but I can't find an archive for it.

For diagnostic purposes please provide the output of the following commands (to be executed in a terminal window):

uname -a
lsb_release -crid
sudo dpkg --audit
ls -l /var/cache/apt/archives/linux-modules-extra-*

$ uname -a

Linux abhishek-Vostro-15-3568 5.4.0-54-generic #60-Ubuntu SMP Fri Nov 6 10:37:59 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux

$ lsb_release -crid

Distributor ID: Ubuntu
Description: Ubuntu 20.04.1 LTS
Release: 20.04
Codename: focal

$ sudo dpkg --audit

The following packages are in a mess due to serious problems during
installation. They must be reinstalled for them (and any packages
that depend on them) to function properly:
 linux-modules-extra-5.4.0-56-generic (no description available)

The following packages have been unpacked but not yet configured.
They must be configured using dpkg --configure or the configure
menu option in dselect for them to work:
 linux-image-5.4.0-56-generic Signed kernel image generic
 linux-modules-5.4.0-56-generic Linux kernel extra modules for version 5.4.0 on
 synaptic Graphical package manager

The following packages are missing the list control file in the
database, they need to be reinstalled:
 linux-modules-extra-5.4.0-56-generic (no description available)

The following packages are missing the md5sums control file in the
database, they need to be reinstalled:
 linux-modules-extra-5.4.0-56-generic (no description available)

$ ls -l /var/cache/apt/archives/linux-modules-extra-*

-rw-r--r-- 1 root root 38534432 Nov 11 04:57 /var/cache/apt/archives/linux-modules-extra-5.4.0-54-generic_5.4.0-54.60_amd64.deb
-rw-r--r-- 1 root root 38572232 Nov 26 04:14 /var/cache/apt/archives/linux-modules-extra-5.4.0-56-generic_5.4.0-56.62_amd64.deb

Thanks Manfred Hampl, that solved my question.