Among the peculiarities of Safari on macOS, the possibility of exporting web pages in WebArchive format, a format that allows you to group text, images, CSS and other content in a single file with the .webarchive extension.
Firefox and Chrome do not offer such a feature (at most they allow you to save a web page including images or as a text file, without preserving the original structure of the HTML links.
To have a function similar to that offered by Safari in Chrome and Firefox, you can take advantage of SingleFile, an extension created by a French developer.
To install on Firefox click on this address, choose "Add to Firefox" and then "Install". To install on Chrome, click on this address, choose "Add" and then "Add extension".
After installation, a small icon will appear in the menu at the top right of the browser. With one click you can save a web page in HTML format complete with images and other files. The images are encoded with the system called "Base64" which allows you to insert the images in HTML with a special string, directly within the page, without the need to recall external files. This mechanism ensures greater compatibility: the files can be opened with any browser, but it is necessary to wait a few seconds during the export phase.