Tried to upload a file to my server and all it does is spit out the curl line each time. I am running Catalina 10.15.3. I looked at your troubleshooting but that isn't an issue I don't use .bashrc. Here is what it does, BTW your .bashrc_Core_Shell is present as well as the line in .bash_profile. Also the download is greyed out even if I highlight a file???
andy@server-2 ~ % curl -fsSL https://raw.githubusercontent.com/codinn/core-shell-scripts/master/bashrc_Core_Shell -o ~/.bashrc_Core_Shell && . ~/.bashrc_Core_Shell && grep -qs ".bashrc_Core_Shell" ~/.bash_profile || echo $'\n[[ -n "$SSH_TTY" || -n "$SSH_CONNECTION" ]] && [ -r "$HOME/.bashrc_Core_Shell" ] && . "$HOME/.bashrc_Core_Shell"' >> ~/.bash_profile