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# Safari Technology Preview 200 Release Notes

Learn about the latest web technology updates in Safari Technology Preview: CSS, JavaScript, Rendering, and Web Extensions.

## Overview

[Safari Technology Preview](https://webkit.org/blog/6017/introducing-safari-technology-preview/) Release 200 is now [available for download](https://developer.apple.com/safari/resources/) for macOS Sequoia beta and macOS Sonoma. If you already have Safari Technology Preview installed, you can update it in System Settings under General → Software Update.

This release includes WebKit changes between: [280675@main…281143@main](https://github.com/WebKit/WebKit/compare/d4bb9d2c03f31fbe54cd1dc7fc27c6628567fe86...958d1de8af7b3bea8e5df94bcf029935abc7b3e0).

### CSS

#### Resolved Issues

- Fixed: Optimized Masonry Grids for items with a span of 1. ([280919@main](https://commits.webkit.org/280919@main))  (131407028)

### JavaScript

#### New Features

- Implemented `Uint8Array.prototype.toHex` in SIMD. ([280719@main](https://commits.webkit.org/280719@main))  (131249821)

#### Resolved Issues

- Fixed class field initializers to disallow `yield` and `await` expressions. ([280837@main](https://commits.webkit.org/280837@main))  (119044881)
- Fixed DestructuringAssignmentTarget to be evaluated prior to calling `[[Get]]` or a stepping iterator. ([281013@main](https://commits.webkit.org/281013@main))  (121960976)
- Fixed throwing an exception for negative exponent in BigInt in the JIT compiler. ([280841@main](https://commits.webkit.org/280841@main))  (131051084)
- Fixed RegExp range quantifier to allow 2^53 - 1. ([280953@main](https://commits.webkit.org/280953@main))  (131710011)

### Rendering

#### Resolved Issues

- Fixed garbled bold text caused by glyph lookup using the wrong font’s glyph IDs when multiple installed fonts have the same name. ([281022@main](https://commits.webkit.org/281022@main))  (129891005) (FB13909556)
- Fixed scrolling of content overflowing a flex item in an end-aligned flex container. ([279992@main](https://commits.webkit.org/279992@main))  (131201271)

### Web Extensions

#### Resolved Issues

- Fixed Service Workers not appearing in the Develop menu or remote Web Inspector menu. ([280912@main](https://commits.webkit.org/280912@main))  (130712941)

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