The release of web browser Firefox 91 has taken place. Firefox 91 is classified under the long-term support (ESR) branches, with updates being issued over the course of a year. Additionally, an update for the previous long-term support branch 78.13.0 has been released (with two more updates, 78.14 and 78.15, expected in the future). The Firefox 92 branch will soon enter beta testing, with its release scheduled for September 7.
Key innovations:
- In private browsing mode, the HTTPS-First policy is enabled by default, similar to the previously available "HTTPS Only" option in settings. When attempting to open a page without encryption over HTTP in private mode, the browser will first try to access the site via HTTPS ("http://" is changed to "https://") and if that attempt fails, it will automatically revert to the unencrypted site. An important difference from the HTTPS Only mode is that HTTPS-First does not apply to loading subresources such as images, scripts, and stylesheets, only acting when attempting to open a site after following a link or entering a URL in the address bar.
- The print output mode has been restored, providing a condensed version of the page reminiscent of Reader Mode, where only significant text is displayed and all accompanying control elements, banners, menus, navigation bars, and other non-content-related parts of the page are hidden. This mode is activated by engaging Reader View before printing. Support for this mode was discontinued in Firefox 81 following the transition to the new print preview interface.
- The capabilities of the Total Cookie Protection method have been expanded, which is activated in private browsing mode and when selecting strict content blocking mode. This mode implies the use of a separate isolated storage for cookies for each site, preventing cookies from being used to track movement between sites, as all cookies set by third-party blocks loading on the site are tied to the main site and are not transferred when accessing these blocks from other sites. The new version changes the cookie cleaning logic to eliminate hidden data leaks and adds user notifications about sites that store information locally.
- The logic of saving files opened after downloading has been changed. Files opened after downloading in external applications are now saved in the default 'Downloads' folder instead of a temporary folder. Firefox offers two download modes — saving and opening in an application. In the latter case, the downloaded file was saved in a temporary folder that was deleted after the session. This behavior frustrated users who needed direct access to the file, as they had to search for the temporary folder where the file was saved or re-download the data if the file had already been automatically deleted.
- Almost all user actions have been optimized with 'catch-up paints', which has improved the responsiveness of most operations in the interface by 10-20%.
- Support for Single Sign-On (SSO) technology has been added to builds for the Windows platform, allowing users to connect to sites using credentials from Windows 10.
- In the builds for macOS, high contrast mode is automatically enabled when the 'Increase Contrast' option is activated in the system.
- The 'Switch to Tab' mode, allowing users to navigate to a tab from the recommendations list in the address bar, now also covers pages in private browsing mode.
- The Gamepad API is now only available when opening a page in a secure context (Secure Context), that is, when accessed via HTTPS, through localhost, or from a local file.
- The desktop version includes support for the Visual Viewport API, which allows you to determine the actual visible area considering the on-screen keyboard or scaling.
- Methods added: Intl.DateTimeFormat.prototype.formatRange() — returns a localized and formatted string with a date range (e.g., "1/05/21 – 1/10/21"); Intl.DateTimeFormat.prototype.formatRangeToParts() — returns an array with locale-specific parts of the date range.
- The property Window.clientInformation has been added, similar to Window.navigator.
In addition to new features and bug fixes in Firefox 91, 19 vulnerabilities have been resolved, of which 16 are marked as critical. Ten vulnerabilities (classified under CVE-2021-29990 and CVE-2021-29989) are caused by memory issues, such as buffer overflows and accessing already freed memory areas. These problems could potentially allow an attacker to execute malicious code by opening specially crafted pages.
Source: opennet.ru
