Displays all links to external workbooks. These are normally by way of formulae that can be easily identified as they have an external workbook name prefixed. e.g.

This linking causes a dialog to show when opening the workbook asking if you wish to update these external links. If you select to 'Update' Excel will update all formulae that refer to external links with new data, if applicable. This can take some time in multiple linked books. Selecting 'don't Update' will leave the values of the formulae at the last refresh.h.

Unlike VBA code the linked workbook does not need to be open to access the data. This is therefore a great way of recovering data from a corrupted workbooks, by setting up linking formulas to it and then pasting the 'values only' after success.

The dialog for 'Links...' (Above) shows the address and file for the link(s) and gives the ability to change the source workbook, update manually or automatically, etc. In latter version of Excel you also have the ability here to 'break' the link, etc.  Links may not only be set up in worksheet formulae, but can be set up in range names, chart sources, etc. If you are finding links troublesome, despite search for offending formulae and copying, paste special...Values in an effort to kill them, you could download Bill Manville's findlink.xla, which will certainly handle the issue.