What is the Spectral Form Factor?

In many papers in Random Matrix Theory [1-3] related to quantum chaos (and, in particular, to the SYK model) they analytically continuate the partition function of the system $$Z(\beta)$$ into $$Z(\beta + it)$$ and then define the Spectral Form Factor like

$$$$g(\beta,t)=\langle Z^*Z\rangle$$$$

They then claim that the specific shape of this function gives a lot of information about the level statistics of the system. Is there any paper or book where I can read a good introduction on these tools? Every paper I found doesn't explain anything in great detail and just shows graphs.

[1] J. Liu, "Spectral form factors and late time quantum chaos", Phys. Rev. D 98 086026 (2018), arXiv:1806.05316.

[2] A. Gaikwad and R. Sinha, "Spectral form factor in non-Gaussian random matrix theories", Phys. Rev. D 100 026017 (2019), arXiv:1706.07439.

[3] J. S. Cotler, G. Gur-Ari, M. Hanada, J. Polchinski, P. Saad, S. H. Shenker, ... and M. Tezuka, "Black holes and random matrices", J. High Energ. Phys. 2017, 118 (2017), arXiv:1611.04650.