grub-common vs. grub2-common

What is the difference between these two packages?

I ask because this stems off of a recent issue other users seem to be having with grub and it breaking after each time windows in accessed (here is an example of such a question: Failed to open \EFI\UBUNTU\*garbled* - Invalid parameter).

I ran sudo update-grub and it fixed the problem for the most part. The errors I get still are:

Failed to open \EFI\UBUNTU*gargled gibberish* - Invalid Parameter

Failed to load image \EFI\UBUNTU*garbled gibberish*: Invalid Parameter

start_image() returned Invalid Parameter, falling back to default loader

Now that I can load into Ubuntu without having to had run boot-repair, I checked all packages I have install with the word 'grub' in them and I noticed that I have "grub2-common" and "grub-common" installed, with their respective subsequent packages installed too. My assumption is that they both represent their respective bootloader versions but I'm not well-versed at all in this general topic.

Any answers that you have through your experience and knowledge are most appreciated!

If you view the package details you'll see

Note: I'm using detail I've copied from terminal (eg. apt-cache show grub-common) but also package links for viewing some details online. You didn't mention a release, so I've used by own (easiest).

grub-common

https://packages.ubuntu.com/impish/grub-common

 Description-en_AU: GRand Unified Bootloader (common files)
 This package contains common files shared by the distinct flavours of
 GRUB. It is shared between GRUB Legacy and GRUB 2, although a number of
 files specific to GRUB 2 are here as long as they do not break GRUB
 Legacy.

ie. it contains common files for legacy grub.

grub2-common

https://packages.ubuntu.com/impish/grub2-common

 Description-en_AU: GRand Unified Bootloader (common files for version 2)
 This package contains common files shared by the distinct flavours of
 GRUB. The files in this package are specific to GRUB 2, and would break
 GRUB Legacy if installed on the same system.

Your system has both, as it then has capacity to deal with any found OSes that are using legacy grub, plus the more modern grub. This is normal.