Inkscape

In Inkscape v1.3 the symbol library displays in XML stack order only.
-This z-axis restacks the symbols in alphabetical order
-This functions similar to Arrange>Restack extension by sorting symbols in the Z-axis.
-For use in managing symbol library file and is intended to aid symbol library creation only. Other uses not tested.

-"Alpha-Numeric Sort Symbols..." placed in Extensions>Symbols

-Whilst this does reorder the SVG XML file structure and it is likely that
1.31 or later version will provide inbuilt non-structural sorting, but in the interim this is probably of use to some as an extension to allow the display of your symbols in alpha-numeric order.

Other Symbol management extensions available:
-Batch Add & Sort (with Quick Batch Add)
-Batch Remove (with Quick Remove Selected)