“Anyone know how someones eligibility is contested? I presume its in court and I presume whoever files must have standing. Would it be done via civil lawsuit or ?”
Yeah.
Anyone can contest it.
You can contest it.
“You can contest it.”
Not gonna happen.
Not true. Only the electors or a direct participant would have “standing”. Obama’s case was dismissed under the courts deciding that the plaintiffs did not have standing so it never addressed any substantive issue.