abap/dyn_abap_log_storage_days is a SAP Parameter attribute which is used to control Dynamischen ABAP: Aufbewahrungszeit des Logs in Tagen 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 .
The value of this parameter is specified in days. Once this number of
days has been exceeded, the system automatically removes the old data.
The value 0 means that the data is not to be removed from the system.
You should only set this value if the data is removed from the system by
other processes.
For more information, see SAP Note 1655743.
See SAP Parameter Documentation for full SAP documentation for this profile parameter.