zbar is used for webcams to scan a QR code and to decode it.
E.g. you have an invoice with a QR code shown on your phone screen and you hold it up to your laptop camera. The laptop would then need to have the zbar library.
Clicking the URL below will take you to a page of Debian's website in which a list of packages of zbar libraries are available for installation:
https://packages.debian.org/search?keywords=zbar&searchon=names&suite=stable§ion=allWhich of these packages should I install?
By the way, my desktop environment is LXQt.
If you don't need this feature, it is safe to ignore.
Thanks for your answer.