项目名称与简介(Project Intro.)

Flathub
From its website:

Flathub aims to be the place to get and distribute apps for Linux. It is powered by Flatpak which allows Flathub apps to run on almost any Linux distribution.

（懒得翻译了，躺）

上游地址与镜像方法(How to Mirror)

https://dl.flathub.org/repo/

It's based on OSTree, so it may be possible to mirror it by using the ostree command.
它的仓库基于 OSTree，所以有可能使用 ostree 来镜像。

See Mirroring repositories for more information.

其他信息(Other)

• 镜像大小(Mirror Size): 未知 Unknown

This idea hasn't been tested yet, so I'd like to discuss it.
目前未经测试，仅仅提出一个想法。

这个 issue 用英语写了一部分是为了更方便得到帮助，也算是一种练习吧（？）
有错请指出，谢谢了:)