extensions/markdown-language-features/src/preview/previewManager.ts/PreviewStore/get
class PreviewStore:	public get(resource: vscode.Uri, previewSettings: DynamicPreviewSettings): T | undefined {
		const previewColumn = this._resolvePreviewColumn(previewSettings);
		for (const preview of this._previews) {
			if (preview.matchesResource(resource, previewColumn, previewSettings.locked)) {
				return preview;
			}
		}
		return undefined;
	}