~/test $ termux-apt-repo . repo stable main -s
Adding deb file: qt-creator_4.12.4-6_aarch64.deb...
Creating package file for main and aarch64...
Signing with gpg...
Done!

Make the repo directory accessible at $REPO_URL

Users can then access the repo by adding a file at
   $PREFIX/etc/apt/sources.list.d
containing:
   deb [trusted=yes] $REPO_URL stable main

[trusted=yes] is not needed if the repo has been signed with a gpg key
~/test $ ls
qt-creator_4.12.4-6_aarch64.deb  repo
/test $ apt update
Hit:1 http://127.0.0.1:8080 stable InRelease
Err:1 http://127.0.0.1:8080 stable InRelease
  The following signatures couldn't be verified because the public key is not available: NO_PUBKEY CAABE459FE4A7128
Get:2 https://tur.uchkks.com tur-packages InRelease [14.0 kB]
Get:3 https://mirrors.ustc.edu.cn/termux/apt/termux-main stable InRelease [14.0 kB]
Get:4 https://mirrors.ustc.edu.cn/termux/apt/termux-root root InRelease [14.2 kB]
Get:5 https://mirrors.ustc.edu.cn/termux/apt/termux-x11 x11 InRelease [14.0 kB]
Fetched 56.2 kB in 8s (7185 B/s)
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
15 packages can be upgraded. Run 'apt list --upgradable' to see them.
W: An error occurred during the signature verification. The repository is not updated and the previous index files will be used. GPG error: http://127.0.0.1:8080 stable InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY CAABE459FE4A7128
W: Failed to fetch http://127.0.0.1:8080/dists/stable/InRelease  The following signatures couldn't be verified because the public key is not available: NO_PUBKEY CAABE459FE4A7128
W: Some index files failed to download. They have been ignored, or old ones used instead.
~/test $