How does docker-php-ext-enable work?

after executing this command, you can open an extension, but I don"t quite understand what this principle is. I wish I couldn"t find the line that opened the extension in the php.ini configuration file.
I hope seniors can explain this.

Mar.02,2022

isn't it

    ini="$PHP_INI_DIR/conf.d/${iniName:-"docker-php-ext-$ext.ini"}"
    if ! grep -q "$line" "$ini" 2>/dev/null; then
        echo "$line" >> "$ini"
    fi
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