EN
Let M be a separable $C^{∞}$ Finsler manifold of infinite dimension. Then it is proved, amongst other results, that under suitable conditions of local extensibility the germ of a $C^{∞}$ function, or of a $C^{∞}$ section of a vector bundle, on the union of a closed submanifold and a closed locally compact set in M, extends to a $C^{∞}$ function on the whole of M.