Paste uses the cgi package extensively in the main code as well as in tests.
The package is deprecated and will be removed in Python 3.13.
The main functions used are escape and FieldStorage. Replacing escape is fairly straightforward, FieldStorage less so.
This issue has been created to highlight that this is coming.
cgitb is also used and will be removed in the same Python version.
Fixes from consumers of Paste encouraged.