You can:

Modify the code for your own personal private use, so long as the modified code is significantly dissimilar from the original code.
Use the pull request feature.
Create a Fork of this repository if you satisfy the following conditions:
- You do not change the package base name. (com.tcn or com.tcn.dimensionalpocketsii)
- You do not remove or change any references to the original Mod Author.
- You do not remove or change any links to the public Mod page.
- You do not change the MOD_ID. (dimensionalpocketsii)
- You are fixing a bug within the code.
- Or you intend to commit to any of the actions listed below under the "You Cannot" section.
Use or copy small portions of code (such as a single method) for personal private use.
Create an Addon Mod that requires this Mod to function.
Include this Mod in a public ModPack if you satisfy the following conditions:
- You include a link to the Mod on the same page as the download for your Pack.
- Include the author name (TheCosmicNebula) above the link.
- You do not re-route the link through comission sites such as Ad.Fly.
Copy any classes that have the #OPEN tag in the comment after the Imports.

You Cannot:

Copy large chunks of code, entire Class files or any assets contained within the Mod.
Redistribute the Mod, unless the link you provide is the original. (CurseForge or GitHub)
Redistribute the Mod under a different name or Author.