How can I disable "seams" on circle/torus when exporting/showing?

[dattasid]

1. What is this? (red arrow) Is "seam" the correct term?
2. Can I choose not to show it when exporting ?

[lorenzncode]

1. What is this? (red arrow) Is "seam" the correct term?

Yes

2. Can I choose not to show it when exporting ?

You can hide edges with cadquery.vis visualization per item styling.

Example:

Set edges=False to hide edges.

from cadquery.func import *
from cadquery.vis import *

sph = sphere(10)

show(
    style(sph, color="green", edges=False),
    style(sph.moved(z=15), color="red", edges=True),
    width=800,
    height=800,
)

Currently, the styling feature is available in the master branch not in the release version.

If you mean exporting to image, latest master also has a screenshot feature - see #1883.