Supposing the internal networks are located through the "Inside" interface.
This line will be saying: when traffic is traveling from inside to outside, sourced with SSL_VPN_NONAT, "keep it" with its same ip address when the destination is SSL_VPN_POOL also "keep it" with its same ip address.
This will be the nat exemption for traffic between local networks and remote pool.
Just to clarify, the first and second line on the nat configuration you shared are defining the traffic the same way.
This line is bi-directional:
nat (Perham-LAN,Outside) source static any any destination static SSL_VPN_POOL SSL_VPN_POOL no-proxy-arp route-lookup
So traffic from Any via Perham-LAN interface and going to SSL_VPN_POOL via outside interface will hit this nat rule, as well as traffic comming from SSL_VPN_POOL via outside going to Any via Perham-LAN will hit this same rule
Hence this second line is not really necessary, and it may cause Reverse Path Failure drops if the ASA detects that one nat is used for outbound traffic and another for inbound traffic on the same connection:
Now the third nat seems correctly configured, however you will need to be careful to configure a dynamic nat as policy nat, this because if new nat rules are added they will show below the currrent nat on the nat table and the dynamic rule may absorb traffic not meant to the rule.