CC 2019. Mac OSX 10.14.6

We have encountered a file corruption whereby we are now unable to open an indesign doc. We get the error message as shown in the screen shot however nobody in our office has this plugin. The operator who created the file cannot even open the file - we are lost as to what has happened to this file as nobody in the team has any additional plugins. We are running the latest version of CC.

Has anybody else come across this issue as we cannot even search online for such a plugin - does it even exist? What has happened?

Any help would be greatly appreciated. Currently we are re-building the file!