To view the low level structure of a GEDCOM file, choose the GEDCOM File Structure option from the main menu. This displays some details about the low level format of the file (character set, line endings etc.), summaries of the numbers of each record type found, and tables listing all the records. The table entries can be clicked-through to display the records behind.
GEDCOM record 'pointers' are shown as links surrounded by @ signs. E.g. '@I1@'. If you click a linked pointer you can see the GEDCOM text for that record. To see an individual presented in the normal, user friendly, way, click the linked name to the right which will take you to the record details page for that record. The raw GEDCOM text is shown indented according to the tag level so as to make it easier to see the structure in the record, and any 'pointers' within will be linked to the target records. This provides a convenient way to browse the internal structure of the GEDCOM.
There is also an option to view the entire GEDCOM file text in a single view; this can be slow with a large GEDCOM but it again will have the pointers linked so you can easily traverse the file. This can be accessed directly from the GEDCOM File Structure page or from the GEDCOM Text tab of the individual record details.
The details pages for all records can include tabs for displaying the underlying GEDCOM file structure: