A2dp library and SD

Im relativley new to arduino and im working on a new project which requires me to simply connect an esp32 to a pair of wireless earbuds. This is achieved by programing the esp32 as a an A2Dp source. The library im using has a built it in function which parses the .wav file and takes in 2 paramters, "fs::FS &fs" and the path which the .wav file is saved in:

bool parseWAV(fs::FS &fs, String path){
char chbuf[256];
audiofile=fs.open(path.c_str());
String afn = (String)audiofile.name(); //audioFileName

if(afn.endsWith(".wav")) {
    audiofile.readBytes(chbuf, 4); // read RIFF tag
    if ((chbuf[0] != 'R') || (chbuf[1] != 'I') || (chbuf[2] != 'F') || (chbuf[3] != 'F')){
        Serial.println("file has no RIFF tag");
        audiofile.seek(0);
        return false;
    }

    audiofile.readBytes(chbuf, 4); // read chunkSize (datalen)
    uint32_t cs = (uint32_t)(chbuf[0] + (chbuf[1] <<8) + (chbuf[2] <<16) + (chbuf[3] <<24) - 8);

    audiofile.readBytes(chbuf, 4); /* read wav-format */ chbuf[5] = 0;
    if ((chbuf[0] != 'W') || (chbuf[1] != 'A') || (chbuf[2] != 'V') || (chbuf[3] != 'E')){
        Serial.println("format tag is not WAVE");
        audiofile.seek(0);
        return false;
    }

    while(true){ // skip wave chunks, seek for fmt element
        audiofile.readBytes(chbuf, 4); /* read wav-format */
        if ((chbuf[0] == 'f') && (chbuf[1] == 'm') && (chbuf[2] == 't')){
            //if(audio_info) audio_info("format tag found");
            break;
        }
    }

    audiofile.readBytes(chbuf, 4); // fmt chunksize
    cs = (uint32_t) (chbuf[0] + (chbuf[1] <<8));
    if(cs>40) return false; //something is wrong
    uint8_t bts=cs-16; // bytes to skip if fmt chunk is >16
    audiofile.readBytes(chbuf, 16);
    uint16_t fc  = (uint16_t)(chbuf[0]  + (chbuf[1] <<8));  // Format code
    uint16_t nic = (uint16_t)(chbuf[2]  + (chbuf[3] <<8));  // Number of interleaved channels
    uint32_t sr  = (uint32_t)(chbuf[4]  + (chbuf[5] <<8) + (chbuf[6]  <<16) + (chbuf[7]  <<24)); // Smpling rate
    uint32_t dr  = (uint32_t)(chbuf[8]  + (chbuf[9] <<8) + (chbuf[10] <<16) + (chbuf[11] <<24)); // Data rate
    uint16_t dbs = (uint16_t)(chbuf[12] + (chbuf[13] <<8));  // Data block size
    uint16_t bps = (uint16_t)(chbuf[14] + (chbuf[15] <<8));  // Bits per sample
    Serial.printf("FormatCode=%u\n", fc);
    Serial.printf("Channel=%u\n", nic);
    Serial.printf("SampleRate=%u\n", sr);
    Serial.printf("DataRate=%u\n", dr);
    Serial.printf("DataBlockSize=%u\n", dbs);
    Serial.printf("BitsPerSample=%u\n", bps);


    if(fc != 1){
        Serial.println("format code is not 1 (PCM)");
        return false;
    }

    if(nic != 1 && nic != 2){
        Serial.print("number of channels must be 1 or 2");
        return false;
    }

    if(bps != 8 && bps !=16){
        Serial.println("bits per sample must be 8 or 16");
        return false;
    }
    bitsPerSample=bps;
    channels = nic;
    sampleRate = sr;
    bitRate = nic * sr * bps;
    Serial.printf("BitRate=%u\n", bitRate);

    audiofile.readBytes(chbuf, bts); // skip to data
    uint32_t s = audiofile.position();
    //here can be extra info, seek for data;
    while(true){
        audiofile.seek(s);
        audiofile.readBytes(chbuf, 4); /* read header signature */
        if ((chbuf[0] == 'd') && (chbuf[1] == 'a') && (chbuf[2] == 't') && (chbuf[3] == 'a')) break;
        s++;
    }

    audiofile.readBytes(chbuf, 4); // read chunkSize (datalen)
    cs = chbuf[0] + (chbuf[1] <<8) + (chbuf[2] <<16) + (chbuf[3] <<24) - 44;
    sprintf(chbuf, "DataLength=%u\n", cs);
    Serial.print(chbuf);
    posDataSection = audiofile.position();
    return true;
}
return false;

}

The problem is that i dont understand the first parameter of the funciton "fs::FS &fs". The example in the library uses the input "SD" in order to play the file from an SD card. I intend to play the wav file located in the same dir as the .ino file, so imnot sure what to replace the "SD" with.