src/vs/editor/contrib/dropIntoEditor/browser/dropIntoEditorContribution.ts/DefaultOnDropProvider/getUriListInsertText
class DefaultOnDropProvider:	private getUriListInsertText(strUriList: string): string | undefined {
		const uris: URI[] = [];
		for (const resource of UriList.parse(strUriList)) {
			try {
				uris.push(URI.parse(resource));
			} catch {
				// noop
			}
		}

		if (!uris.length) {
			return;
		}

		return uris
			.map(uri => {
				const root = this._workspaceContextService.getWorkspaceFolder(uri);
				if (root) {
					const rel = relativePath(root.uri, uri);
					if (rel) {
						return rel;
					}
				}
				return uri.fsPath;
			})
			.join(' ');
	}