The refers to the K class for geometric tolerances (Part 2).
ISO 2768 is commonly used in various industries, including: Iso 2768 General Tolerances Pdf
"General tolerances according to ISO 2768-mK" The refers to the K class for geometric tolerances (Part 2)
Keep in mind that accessing a PDF copy of the standard may require a subscription or a one-time payment. Iso 2768 General Tolerances Pdf