src/vs/workbench/common/editor/sideBySideEditorInput.ts/SideBySideEditorInput/getName
class SideBySideEditorInput:	override getName(): string {
		const preferredName = this.getPreferredName();
		if (preferredName) {
			return preferredName;
		}

		if (this.hasIdenticalSides) {
			return this.primary.getName(); // keep name concise when same editor is opened side by side
		}

		return localize('sideBySideLabels', "{0} - {1}", this.secondary.getName(), this.primary.getName());
	}