What is these parameter? about flatland HOT 1 CLOSED

Those two parameters are the configurations of the physics engine (box2d), as mentioned in the docs:
https://flatland-simulator.readthedocs.io/en/latest/core_functions/world.html

Documentation on what that does here:

https://box2d.org/documentation/md__d_1__git_hub_box2d_docs_hello.html#:~:text=The%20suggested%20iteration%20count%20for,increases%20performance%20but%20accuracy%20suffers.

Basically, lower numbers of iterations will run faster, but the physics simulation will be less accurate since the solver iteratively tries to satisfy all constraints, but when two or more objects collide those constraints conflict with eachother. The iterative solver tries to solve each one in each loop, converging on the a more accurate solution.

Friction can be set on the footprints of models:

https://flatland-simulator.readthedocs.io/en/latest/core_functions/models.html?highlight=friction

The friction set there will apply a counteracting force each timestep towards zero motion based on the friction parameter.

from flatland.