With blender 2.79, i can convert easily particle path to curve in the modifier tab.
With Blender 2.8, i can’t reproduce this.
Is there something under my eyes that i can’t see?
No. The tool has simply not been restored in 2.8.
Is there another way to do this?
I like to make some abstract background this way…
You can create a mesh (a subdivided ribbon or tube aligned to Y axis) and add a Particle Instance modifier referring to particle system (create along path option On, Y axis).
That’s work very well.