Find all files with the extension ".txt" in the current directory and its subdirectories, then use awk to split the file path into its components and use them to construct a URL to download the file from GitHub, then execute the command with bash.
find . -name "*.txt" | awk 'BEGIN { FS = "."; OFS="/" } { print "wget https://github.com/", $2 "/" $3 "/" $4 }' | bash