This will adjust how options are shown to the user without affecting their saved value. <value> will be replaced with the value of the current option. You can use parser functions and wikitext.
wikitext and parser functions allowed (use <subject> and <Property a> to retrieve the values respectively of the query result subjects and of the property with name "Property a")
enter a template/parser function if you want to alter the value of this field before saving. Use <property>, where "property" is the name of either the property related to this field, as well as of other properties in the same form, to use their actual value in the template/parser function
Templates and parser functions allowed, to retrieve the input value of a field associated to a given property use <property> where "property" is the name of a property/field included in the form
Templates and parser functions allowed, to retrieve the value of a mapped field in a given row use <property> where "property" is the name of property / mapped field