"apt-mark showmanual" will show you all packages that you have manually installed
"apt-mark showauto" will show you all packages that are automatically installed
"apt-mark showinstall" will show you all the packages that are installed
How is this useful? It tells you what packages are installed in your system.
So you can go "apt-mark showinstall | grep somelibrary" to see if you have a particular library installed that's a dependency.
Commodore 128 Personal Computer Only ~ Working ~ Tested
$199.99
Commodore SX-64 Custom Made KEYBOARD CABLE ONLY GOOD CONDITION SX64 C-64
$31.99
Commodore SX-64 Card / Board Slot Positioner Lot Of (15) SX64 C-64
$19.99
Vintage Commodore VIC-20 Personal Color Computer in Box W/ Extras
$129.99
1984 Commodore 64 Home Computer PC Color Video Monitor Model 1702 - Tested
$350.00
Vintage Commodore Plus/4 Computer Lot Of 3 Untested Estate Sale Buy Out
$300.00
Professionally restored & fully recapped Commodore 64 computer | NTSC C64
$299.00
Commodore 64, 128 & C-16 Color S-Video and Audio Adapter W/ Chroma Adjuster
$34.00
commodore 64 computer works recapped in original box
$219.00
Commodore SX-64 SX64 Executive Portable Color Computer - See Description
$359.00