What does it mean to be a musician without a trace?

There is no trace of musicians, only the sound of playing the flute. The Musician Without Trace is from Cao Zhi's Diabolo Fu. According to its translation, this sentence means that there are no musicians, only the sound of playing the flute. The next line in the poem is that fairies fly around, which means diabolo flies up and down like an elf with silk thread.