The Travel Tripod is indeed compatible with many Arca-compatible plates and L-brackets.
How? The ball head's removable pins allow longer plates and L-brackets to lock in place.
While Arca is the closest thing there is to a standard tripod plate geometry since about 85% of professional tripods use it, we still say "many" and not "all". We've learned over the years that there can be slight geometric variance across brands.
While this list is by no means definitive, here are a few examples of plates and brackets that have been confirmed to work with the Travel Tripod.
That being said, the best way to get it sorted is to head down to your local Peak Design dealer and get hands on with it.
A Few Examples of Travel Tripod Compatible Plates and L Brackets