I have recently downloaded microarray data from GEO using the following in R (as mentioned in GEO2R)

library(GEOquery)
library(limma)
library(umap)
gset <- getGEO("GSE86971", GSEMatrix =TRUE, getGPL=FALSE)
if (length(gset) > 1) idx <- grep("GPL13684", attr(gset, "names")) else idx <- 1
gset <- gset[[idx]]
ex <- exprs(gset)

the resulted contained row names

mMC002640 , mMC002644 , mMC002645, PH_mM_0000001 , and PH_mM_0000002

The question here is what are the type of identifiers ( for example mMC002640, PH_mM_0000001 ) used for this data? and how can convert those into gene names?