Xyloglucan acetyltransferase that catalyzes the acetylation of fucosylated Gal residues on xyloglucan side chains (PubMed:30083810). Predominantly catalyze 6-O-monoacetylation of Gal residues in the Fuc-Gal-Xyl trisaccharide side chains of xyloglucan oligomers (PubMed:30083810). Involved in xyloglucan specific O-acetylation in seeds (PubMed:22086088). No visible phenotype. Loss of O-acetylated xyloglucan oligosaccharides in seeds, but no effect on xyloglucan O-acetylation in roots and rosette leaves. Contains 2 motifs that are conserved in esterases, but it is unlikely that this protein belongs to the catalytically active pectin esterases. Belongs to the PC-esterase family. TBL subfamily.