gildas-lormeau/SingleFile v1.29.0 on GitHub

New option "custom stylesheet" in the Stylesheets section: CSS inserted as the last stylesheet before the page is read, applied to the page and its frames and saved with the page
The option "remove images for alternative screen resolutions" now also decides whether the alternative images are downloaded. Checked, only the displayed image of an <img> or <picture> is requested, which makes saving faster. Unchecked, the srcset variants are downloaded and kept with their media queries and sizes, so the saved page stays responsive. The hidden option blockAlternativeImages is removed from the settings: it defaulted to on, so unchecking the visible option used to leave empty <source> elements in the saved page instead of the variants
single-file-core is updated from 1.6.25 to 1.6.28, see https://github.com/gildas-lormeau/single-file-core/releases/tag/v1.6.27 and https://github.com/gildas-lormeau/single-file-core/releases/tag/v1.6.28
The image quality option is documented in the Chinese help page

A text resource lost every U+FEFF it held instead of only a leading byte-order mark, so a stylesheet using the character as a zero-width no-break space in content was altered on save
Grouped duplicate images are written in resource order instead of the order their downloads finished, so that part of the saved page no longer varies between two saves