service/https/acl_file is a SAP Parameter attribute which is used to control ACL (access control list) file of sapstartsrv https port 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 file that the start service uses as an
access control list (ACL) for the access authorizations for connections
over its HTTPS port.
If the profile parameter is set, the file must exist and its syntax must
be correct. If this is not the case, the start service ends.
The syntax of the ACL file is described in ACL Syntax.
If the specified ACL file does not exist or is contains errors, the
start service ends immediately.
See SAP Parameter Documentation for full SAP documentation for this profile parameter.