Liquid Rescale is supposed to be included in Gimp 2.9 sometime, until then.
This came up on another forum, but since there are now some Windows Gimp 2.9.6 users here, might be some use.
64 bit Liquid Rescale plugin. I am sure Rod can compile it, but for others, this came from various Partha 64 bit Gimp 2.8 packages you can dig up on the internet archive.
3 files gimp-lqr-plugin.exe plug_in_lqr_iter.exe liblqr-1-0.dll
You can put them all in your plug-ins folder and it works, but strictly
liblqr-1-0.dll should go in Gimp 2.9\bin folder

Not absolutely necessary but if not already done, avoid all those deprecated procedure warnings, add --pdb-compat-mode=on to the Gimp 2.9 shortcut.

Does it work, it does here:

Not the best of examples, but there it is:

Not sure if this is version 0.7.1 or 0.7.2 the files go back to around 2013 so might be 0.7.2