I have read that it is possible to link an SVG file within an SVG file here: https://stackoverflow.com/questions/5451135/embed-svg-in-svg

Can I do this in Inkscape?

This would be very useful such as when creating 2D documentation for manufacturing / construction where you tend to place multiple vector drawings on a single titleblock sheet.

It's possible, but there's no UI for this in released versions of Inkscape.

There will be some support in the upcoming Inkscape 1.0. Feel free to test a development version to see if it suits your needs.

For reference, this is the URL for the feature mentioned above https://wiki.inkscape.org/wiki/index.php/Release_notes/1.0#Linking_and_embedding_SVG_files. It is really great to be able to link SVGs as bitmaps inside inkscape! An additional feature that would be very useful would be if the svg file that is link is pointing to is used when saving in a vector format such as PDF, instead of including the bitmap rendering in the PDF.

I've tried the https://github.com/fsantini/inkscape_LinkSVG  extension and it's working 😃, although it needs some code cleanup for Inkscape 1.0.