Note that codes 58 and 59 are slightly different to the others, in that they do not express a particular file type that ISYS indexes as documents. Rather, these codes act as flags to indicate whether ISYS should subenumerate these container formats. If these formats are set in your ISYS.CFG, then ISYS will look inside these container formats and index whatever files are found within them, subject to the other formats you have nominated.

In other words, a Word document inside a ZIP file is indexed as document type 25, not document type 59. But unless 59 has been given as an allowable format, the ZIP will not be entered during the document scanning phase of an index update.