I can’t see why I would want to do that from your post or the Github readme. Care to elaborate?

I mean, if I’m using an old closed-source application, what would be the advantage of changing its extender?

The DOSBox wiki only provides a vague statement:

  > Once a game uses this, it is expected to run faster and better in DOSBox.

The references on Wikipedia could shed some light

  https://en.wikipedia.org/wiki/DOS/32

The most concrete I've noticed is https://web.archive.org/web/20171224010653/http://dos32a.nar...

  > DOS/32 Advanced DOS Extender provides full compatibility with Watcom C/C++ and features one of the most complete software emulations of DOS/4GW, thus allowing the users to "plug" it into the protected mode programs which use DOS/4G, DOS/4GW, DOS/4GW Professional and any other compatible DOS Extenders without the need to modify a single line of code.
  > 
  > DOS/32 Advanced DOS Extender has been designed to be fast, flexible and reliable. It features very fast mode translation and interrupt servicing, ability to configure and bind the DOS Extender to applications, protected mode executable compression, support for allocation of up to 2 GB of memory, Null-pointer protection and more.

There's also HTML docs in the repo:

  https://github.com/yetmorecode/dos32a-ng/tree/main/doc

DOS/4GW was a limited version of DOS/4G. Early versions had trouble with secondary DMA channels on the ISA bus (wreaking havoc with certain 16 bit soundcards). The 4GW version especially was also considered slow and bloated, and allows only up to 64MB of memory to be used. DOS/32A allowed allocation of up to 2GB, and has better performance and a smaller binary.

That's neat, but I think the DOS era was over well before a 64MB limit became a limitation.

Maybe for very specialized stuff like 3D Studio it'd make a difference.

It might stop crashing after a short amount of time : https://www.gog.com/forum/m_a_x_series/changing_dos_extender...

PMODE/W was also modern... and now it's open-source too: http://www.sid6581.net/pmodew/