login/min_password_uppercase is a SAP Parameter attribute which is used to control minimum number of upper-case characters in passwords information. This is available within R/3 SAP systems depending on the version and release level.
Below is the standard documentation available and a few details of the attributes values .
This parameter specifies the minimum number of uppercase letters that a
password must contain. It applies both when assigning new passwords and
when changing the password or resetting passwords.
This parameter is ignored if the profile parameter
See SAP Parameter Documentation for full SAP documentation for this profile parameter.