@ABHIRAMSHIBU - the signature is valid, you need to import the corresponding public key into your keyring to verify the sources. See the following wiki pages:
==> Verifying source file signatures with gpg...
Python-3.13.1.tar.xz ... FAILED (unknown public key A821E680E5FA6305)
==> ERROR: One or more PGP signatures could not be verified!
There is some problem with signature, the key is using weak SHA-1, so gpg is not accepting it.
Can i be a co-maintainer so i can ensure the python version is up-to-date?
This a build of Python 3.13 with the experimental free-threaded (no GIL) mode enabled. The binaries have a t suffix i.e., python3.13t, idle3.13t and so on; it can be installed alongside other Python packages such as python313 and python.
See https://docs.python.org/3.13/whatsnew/3.13.html#free-threaded-cpython for more details on the free-threaded mode.