/**
 * Unescape a string value used in a GFF3 attribute.
 *
 * @param stringVal - Escaped GFF3 string value
 * @returns An unescaped string value
 */
export declare function unescape(stringVal: string): string;
/**
 * A parsed GFF3 feature: a flat object with 0-based half-open coordinates,
 * numeric strand (`1`/`-1`/`0`), attributes spread as lowercase top-level keys,
 * and child features nested under `subfeatures`.
 */
export interface GffFeature {
    start: number;
    end: number;
    strand?: number;
    type: string | null;
    source: string | null;
    refName: string;
    phase?: number;
    score?: number;
    subfeatures: GffFeature[];
    [key: string]: unknown;
}
/**
 * Parse the 9th column (attributes) of a GFF3 feature line into `result`,
 * lowercasing keys and suffixing any that collide with a default field name.
 * Pass shouldUnescape=false as a fast path for data with no escaped characters.
 */
export declare function parseAttributes(attrString: string, result: Record<string, unknown>, shouldUnescape: boolean): void;
/**
 * Parse a GFF3 feature line. Unescaping is skipped entirely for lines with no
 * '%' character, which is the common case.
 *
 * @param line - GFF3 feature line
 * @returns The parsed feature
 */
export declare function parseFeature(line: string): GffFeature;