I want to check the Apache AllowEncodedSlashes configuration.

As far as the document is concerned, the default value seems to be "Off".

AllowEncodedSlashes Directive

Also, it seems that you can use the following command to verify the location and contents of the configuration file.
(This is an example on Linux, so I haven't tried to see if I can use FreeBSD as it is.)
Also, I think you will need to have the appropriate access rights to check the contents of the configuration file.

Get Apache information on the command line - Qiita

Getting a List of Configuration Files

httpd-t-DDUMP_CONFIG2>/dev/null | grep'#In' | awk' {print$4}'

Getting the Contents of the Configuration File

httpd-t-DDUMP_CONFIG2>/dev/null | grep-v'#'