difference between /configs, /mmdet3d/configs and /projects

[furyNerd]

hi, i'm new to mmdet3d and still learning.

can i have some brief introduction about the purposes and differences between folders:
/configs
/mmdet3d/configs
/projects
/projects/${SOMEONE}/configs

according to mine, /projects and its subdirectory looks like for some newly developed models as well as the corresponding implementations, e.g. operators, tools or APIs.

/configs includes some fully developed models or components, but what's the purposes and differences between /configs and /mmdet3d/configs?

e.g.:

/configs/centerpoint/centerpoint_pillar02_second_secfpn_8xb4-cyclic-20e_nus-3d.py

/mmdet3d/configs/centerpoint/centerpoint_pillar02_second_secfpn_8xb4_cyclic_20e_nus_3d.py

is /configs for demonstrations and /mmdet3d/configs for lib installation (like in pip)? is the naming-styling difference like 8xb4-cyclic and 8xb4_cyclic means something?

thanks for any advice.