DIN 26727 is part of the larger DIN 267 series, which covers fasteners (bolts and nuts). The specific distinguishing features of DIN 26727 nuts are:
Legally, you cannot get it free from unauthorized sources. Official options: din 26727 pdf hot
Be very careful with websites offering "Free PDF downloads" of ISO or DIN standards. These sites are frequently infected with malware or adware. DIN 26727 is part of the larger DIN