Let’s suppose you want to download a Plugin and it is no longer available to download from wordpress.
For example, https://wordpress.org/plugins/contact-widgets/
So were on version 1.2.0 of contact-widgets, and the lastest version showing on wordpress page is 1.7.0
The download will be
https://downloads.wordpress.org/plugin/contact-widgets.1.7.0.zip
You can change the number for the version you would like and you can get version from https://wordpress.org/plugins/contact-widgets/#developers
Under “development log”
And change the version number like this:
https://downloads.wordpress.org/plugin/contact-widgets.1.2.0.zip
Just visit the link and it will downlaod the plugin.
Same for the theme too.
Just change the plugin to theme in the url
https://downloads.wordpress.org/theme/any-theme.1.1.0.zip