mike-burns/aeson — comment on commit 4fbd5b9139d487dd7eb00fe5674e424489a85b7c
File: Data/Aeson/Types/Class.hs line 623
By hvr:

The comment in https://github.com/bos/aeson/issues/1#issuecomment-777020 w.r.t. to millisecond precision applies here as well (`%Q` has much more decimals than supported by ECMA-262 -- actually the ECMA-262 spec seems to require exactly 3 digits even in case of trailing zeros)