Which private key format is this?
Probably encrypted using an OpenSSL-interoperable format. See 

https://crypto.stackexchange.com/questions/8776/what-is-u2fsdgvkx1/8777#8777

http://juliusdavies.ca/commons-ssl/pbe.html

The 8 bytes following "Salted_" should be the salt.

Example cmdline to decrypt:

echo 'U2FsdGVkX19qplb9qVDVVEYxH8wjJDGpMS+F4/2pS2c=' | openssl enc -a -d -salt -des3 -pass pass:changeit
Hello World!