DNA glycosylase with broad substrate specificity. Can remove uracil from double-stranded DNA containing either a U/G or U/A base pair. Can also process hydroxymethyluracil (mispaired with guanine or adenine), hypoxanthine and fluorouracil. Exhibits a clear preference for double-stranded DNA substrates, but can also process uracil in single-stranded DNA, with lower efficiency. Thermostable. Belongs to the uracil-DNA glycosylase (UDG) superfamily. Type 5 (UDGb) family.