This is where you can control how tag name programs function by enabling or disabling them and turning on or off the flags that affect the behavior of tag name programs.
Validator Engine Options Flags Page
A tag name program is primarily a program that is executed when a certain tag or attribute is encountered in an HTML or XHTML document. The tag name program typically performs additional syntax checking and may generate validator messages (such as error or warning messages) if a syntax problem is found.
•Program Flags - Check and uncheck these flags to enable or disable tag name program flags that are used in tag name programs. This allows a tag name program to be written so that certain behaviors of the tag name program can be instantly changed by checking or unchecking a flag. For instance, tag name programs can be written to warn users about using tags that may only work in certain browsers. If you do not want to see these warnings, a tag name program can be written so that the warnings will not be generated if a certain flag is unchecked. In this case, you can easily enable or disable these warnings by unchecking the appropriate flag or flags. The default is all flags checked (set). What do the flags do?