How do I sync a repo I've forked on GitHub without creating a commit in the parent?
I've found several sources of instructions (for example this and this, as well as a few related questions on SO) which seem to generally agree on how to accomplish this; but all are at least many months old, and none are 100% clear on whether the procedure creates a commit in the parent repo.
Can I sync a repo I've forked on GitHub without creating a commit in the parent? Will these procedures create a commit in the parent repo?
If by "parent" you mean the original repo you forked from, then yes, the methods you link to do update your fork with the latest changes from the "parent" repo (for the selected branch) without changing the "parent" repo.
In general, pull requests (PRs) do not have to originate from the fork and target the "parent" repo, it can also be the opposite way (as shown in your linked articles). You can also file PRs from one branch to another branch within the same repo.