I found an interesting code for LilyGO TTGO T5-4.7" and I would love if someone explained the code to me

Projects Programming
6 
// Read data from the web server
bool read_web_data()
{
    HTTPClient HTTP;
    // currency_names: {"Bitcoin", "Ethereum", "Litecoin", "Monero"};
    String cur = currency_names[currency_index];
    cur.toLowerCase();  // Force to lowercase
    String uri = "/public/v1/coins/" + cur + "?currency=EUR";
    // Get a quote (in euros) for the specified cryptocurrency  
   // "https://api.coinstats.app/public/v1/coins/bitcoin?currency=EUR"
    // Pass a list of root certificates so the identity of the server
    // can be validated.
    http.begin("https://api.coinstats.app" + uri, root_ca);
    int httpCode = http.GET();
    bool success = false;
    if (httpCode == HTTP_CODE_OK)
    {
        if (decode_web_data(http.getStream()))
            success = true;
        else
            Serial.println("Web data decoding failed");
    }
    else
    {
        Serial.printf("Connection to API failed, error: %s\r\n", http.errorToString(httpCode).c_str());
    }
    http.end();
    return success;
}