Legal disputes are often settled by a bench trial where a judge, rather than a jury, renders the verdict. According to Mass. Civ. Pro. Rule 52(a),
In all actions tried upon the facts without a jury, the court shall find the facts specially and state separately its conclusions of law thereon…
The notes to Rule 52 say,
Requiring a party to submit proposed findings and rulings as a condition to the court’s making findings and rulings is justified by the volume and nature of the civil caseload
In other words, a judge may–and often will–order both parties will submit their “findings of fact” and “conclusions of law.”
These are essentially each side’s proposed judgment, supported by legal reasoning.
The judge’s final opinion is usually written largely from these documents.