You Do Need power plug adapter while traveling from Swaziland to Libya.

Here is Why You Need An Adapter

The outlet and plug type used in Libya are C and L and in Swaziland is M. This is how they look like.

Swaziland

In Swaziland, outlets of type M are in use.

Type M

Libya

In Libya, outlets of type C and L are in use.

Type C

Type L