Unique filter.
Yeah, I've seen a few Malleys Whirlpools with that type of lint filter. I believe that attachment is unique to the Malleys style of Whirlpool which is found in Australia. It is very similar to the filters found in US Speed Queens back in the '60s.
When the agitator shifts directions, the paddles built around the rim of the pan will shovel wash water upwards and into the pan where the lint can be trapped. It does capture lint okay, but from what I've seen, its effectiveness is debatable. I still think it's a pretty clever design nonetheless.