Pseudo-Attribute Processing Instructions
The pseudo-attribute processing instruction (PI) indicates that a pseudo-attribute has a value for a given tag. This type of PI is visible only in the SGML source.
For example, the processing instruction
<?Pub LcL _id="f1">
indicates that the preceding element has the _id pseudo-attribute set to f1.
You can delete pseudo-attribute PIs using the write -nopi command. You can also manipulate them using ACL functions such as oid_delete_attr and oid_modify_attr. > does not locate pseudo-attribute processing instructions.