This is interesting. Double weapons are of course bound to chinese fighting systems. Donn F. Draeger in his book "The weapons and fighting arts of Indonesia" describes a fighting system called Kuntao. After a quick lecture I have an impression, Kuntao can be found in places in Indonesia with an intact chinese community, which probably means ewerywhere; Sumatra, Java, Madura, Sulawesi (Makassar) are mentioned. On page 207, there a sinistre looking guy with two similar choppers is depicted (illustrating Kuntao in Makassar), yet they are called Parang (probably the Parang Upacara mentioned in Zonneveld, the source beeing Draeger

)
These could be Javanese, they are very popular in Sunda.