Within the Coruscant Jedi Archives (as shown), one could discover spinner-webs in the Archive of Forbidden Artifacts.
Spinner-webs are defined as a particular kind of substance. Back in 88 BBY, Sifo-Dyas and Dooku, who were Jedi Initiates at the time, stumbled upon spinner-webs when they broke into the Archive of Forbidden Artifacts. This archive was a clandestine vault containing dark side artifacts, and it was situated inside the Jedi Archives of the Jedi Temple which stood on the planet of Coruscant. Dooku felt disgust towards the copious amounts of spinner-webs present within the vault, while Sifo-Dyas didn't give the substance much thought.
Later, Dooku communicated the events to Jenza, his sister, through a holo-letter. Around 23 BBY, Dooku handed over several data disks, which held his messages to Jenza, to Asajj Ventress, his newly appointed Sith assassin. This was for her investigation into his sister's whereabouts, and she subsequently listened to the holo-disk that made mention of spinner-webs.
The audio drama Dooku: Jedi Lost, penned by Cavan Scott and released on April 30, 2019, featured spinner-webs in a flashback sequence. The script release of the audio drama, which occurred on October 1 of that same year, officially verified the spelling of "spinner-webs."