Files with zdl extension can be mostly found as label designs created using DesignPro label designing software.
ZDL file extension - DesignPro label design (version 5.0)
What is zdl file? How to open zdl files?
File type specification:
File extension zdl is associated with DesignPro for PC, a label designing program, developed and sold by Avery.
A .zdl file contain label design created and and saved in DesignPro.
Older versions of DesingPro used the zdb file extension instead.