1. Animated PNG (APNG)

    Like animated GIFs, but allowing 24-bit colors and alpha transparency

  2. AVIF image format

    A modern image format based on the [AV1 video format](/av1). AVIF generally has better compression than [WebP](/webp), JPEG, PNG and GIF and is designed to supersede them. AVIF competes with [JPEG XL](/jpegxl) which has similar compression quality and is generally seen as more feature-rich than AVIF.

  3. HEIF/HEIC image format

    A modern image format based on the [HEVC video format](/hevc). HEIC generally has better compression than [WebP](/webp), JPEG, PNG and GIF. It is hard for browsers to support HEIC because it is [complex and expensive to license](https://en.wikipedia.org/wiki/High_Efficiency_Video_Coding#Patent_licensing). [AVIF](/avif) and [JPEG XL](/jpegxl) provide free licenses and are designed to supersede HEIC.

  4. JPEG XL image format

    A modern image format optimized for web environments. JPEG XL generally has better compression than [WebP](/webp), JPEG, PNG and GIF and is designed to supersede them. JPEG XL competes with [AVIF](/avif) which has similar compression quality but fewer features overall.

  5. JSON parsing

    Method of converting JavaScript objects to JSON strings and JSON back to objects using JSON.stringify() and JSON.parse()

  6. WebP image format

    Image format (based on the VP8 video format) that supports lossy and lossless compression, as well as animation and alpha transparency. WebP generally has better compression than JPEG, PNG and GIF and is designed to supersede them. [AVIF](/avif) and [JPEG XL](/jpegxl) are designed to supersede WebP.

  7. javascript built-in: json: stringify

  8. javascript built-in: json: stringify: strings are escaped to well-formed utf-8

  9. ecmascript 2019 (es10)