"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.
New Precision DWDM SFP+ 10G 80km Tunable Transceiver 50GHz C-Temp DWDM-SFP10G-C
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Original CISCO SFP-10G-SR V03 10-2415-03 850nm 10GBASE-SR SFP+ Multi mode Module
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Brand New Cisco GLC-LH-SMD 1000BASE-LX/LH SFP Module 1310nm 10km SMF LC
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Precision PRE-SFP-TMI-CSCO 1GB BASE-T RJ-45 SFP Transceiver - For Cisco
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CISCO SFP-10G-LR SFP TRANSCEIVER MODULE GBIC 10G 10GB SFP - 1 Year Warranty
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NEW FS SFP-10G-T 10GBASE T SFP+ 30M Transceiver Module (Lot of 1 Unit)
$39.95
New HP HPE Aruba J9150D 10G SFP+ LC SR 850nm 300m MMF XCVR Transceiver Module
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10 PCS Cisco GLC-LH-SMD 10-2625-01 1310nm SFP Transceiver Module
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