I've updated X mods for B18, whats the proper courtesy?

[FrodoOf9Fingers]

I've updated a few mods for my own use for B18. Some, I've listed in the relevant github repos or steam workshop pages as an "unofficial" update, but I'm not sure if thats the best way to go.

Disregarding individual licensing (assume all mods I talk about have no license listed), what is the proper way to release mod updates that won't offend?

A few mods I've update have not been updated officially for some time. Is it right to snag the code and change it to my own tastes, and only list the original author as an original author? The EULA states I can, -but- I disagree with the terms of the EULA (although I follow it), and would prefer an argument based on courtesy rather than legality.

So, the TL:DR....

1. Assuming the original author cannot be reached, how should I annotate/publish an update to a mod?
2. Assuming the original author cannot be reached, how should I annotate/publish a mod using code from another mod, but drastically altered? Is it even right to do so, should I be expected to start from scratch?

[NiftyAxolotl]

You are on the right track: see Homesteading the Noosphere
With no hints as to the author's intent for the license, the general rule in software is that you have no permission to copy. But these mods are in a context (the EULA) that supersedes that rule.
If you're willing to hand control back to the original author when they contact you - including your changes - then fork without guilt (after the proper announcements and such).

[Dashthechinchilla]

Some of it reminds me of abandonware. The mods may not be updated and maintained by the owner, and they may never care enough to seek you out, but technically they can at any time.

[SpaceDorf]

The common curtesy for case 1.)  I noticed on the forum was to

a.) pm the author
b.) read the licence or comment in first post, if no comment to sharing is made, I would assume that the modder has not thought enough about it to care.
c.) post in the mods thread to announce the unofficial update, with the promise to remove or return it to the creator.

In case 2. I am not sure, even if you start from scratch you could arrive at the same code the original auther wrote.
If you use the code/mod idea for inspiration and drastically alter it so much, that you could have written it by yourself I would republish the mod, maybe under the same name and clearly credit the original author.