"Structure" is honest bookkeeping. A bump in a mass distribution earns the word "state" when its mass and width reproduce in another dataset, analysed by other people with other background models, and neither of these two has been through that yet [2].
Where they came from is the interesting part of the method. Many XYZ candidates live in the charmonium and strangeonium regions of the hadron spectrum, where a quark pairs with its own antiquark and the masses crowd together [8]. BaBar made its strangeonium candidate the standard way, by colliding negatively charged electrons with their positively charged antimatter counterparts [5]. The Jefferson Lab route shares neither beam nor background with that, and the detector sits in Experimental Hall D, home of the Gluonic Excitations collaboration, which is what the G in GlueX stands for [1]. The practical consequence is that the failure modes on the two sides are not the same failure modes.
Twenty years separate BaBar's 2006 report from the release of this result [9]. That is a fair measure of how slowly an independent handle on a single exotic candidate arrives.
The label doing the most work here is also the least informative one. XYZ is what physicists settled on for the hadrons that began appearing after the turn of the century with quantum properties the original quark model could not hold [12], objects that do not sit neatly in the picture of particles built from quarks [14]. Compare that with how the model grew the last time it was stretched: three flavors in 1964, up, down and strange [10], then the charm quark in 1974, an eventual six flavors and the framework that became the Standard Model [11]. Those additions explained something. XYZ, so far, only sorts things. Frank Nerling of GSI Helmholtz Centre and Goethe University Frankfurt, a Jefferson Lab collaborator, put the parallel as a zoo of hadrons discovered first and a zoo of exotic states now [7].
The summary Jefferson Lab released with the work is thin on the quantities that decide these arguments, so the read here rests on the channel rather than on the peaks. Its stated hope is that results of this kind help show how quarks and gluons combine to create matter [15]. That hope is checkable, and these two structures are where the checking starts.
