Testing via local manifest fails due to error in loading installers index

PERSONAL_DEPENDENCIES がローカルの index.yml を指し、PERSONAL_INSTALLERS が GitHub リポジトリと index.yml の URL を指すようにして、報告されたコマンドを再現します。リポジトリ読み込みのエントリポイントを追跡し、それぞれの URL がどのように解釈されるかを確認します。完了条件は、両方のリポジトリでインデックスが読み込まれ、報告されたエラーなしに利用可能なインストーラーが表示されることです。

I was planning to create some installers for software i used to use. However, i am getting errors when to read the fork's index.yml.

Starting bottles using the following command i get the following

PERSONAL_DEPENDENCIES=file:///home/MY_USERNAME/.bottles/local_installers/programs/index.yml flatpak run com.usebottles.bottles
...
20:58:39 (INFO) Using personal dependencies repository at file:///home/MY_USERNAME/.bottles/local_installers/programs/index.yml 
20:58:39 (ERROR) Could not get index for dependencies repository: (37, "Couldn't open file /home/MY_USERNAME/.bottles/local_installers/programs/index.yml/index.yml") 
20:58:39 (ERROR) Could not get index for dependencies repository 
...

Permissions have been checked but without further progress. Then i tried to read from a git repository. But even reading from the official's repo main branch results in errors:

PERSONAL_INSTALLERS=https://github.com/bottlesdevs/programs/tree/main flatpak run com.usebottles.bottles
...
21:02:15 (INFO) Catalog components loaded 
21:02:15 (ERROR) Cannot fetch installers repository index. 
21:02:15 (INFO) No installers found! 

PERSONAL_INSTALLERS=https://github.com/bottlesdevs/programs/tree/main/index.yml flatpak run com.usebottles.bottles
...
21:02:44 (INFO) Using personal installers repository at https://github.com/bottlesdevs/programs/tree/main/index.yml 
21:02:45 (ERROR) Could not get index for installers repository 

I am running out of options and can not see any obvious errors. Since the terminal log is limited I don't know which steps i should go to progress.