Multiple dashboards and resources configuration

This past weekend I started playing with additional Dashboards in YAML Mode. My question for the guru’s is this; do resources need to be defined in ui-lovelace.yaml as well as configuration.yaml (see my attached code for a very trimmed down version of my config)

[from ui-lovelace.yaml]

title: My Home Assistant
resources:
#   ----------------------------------------------------------------------------
# Mini Graph Card
  - url: /community_plugin/mini-graph-card/mini-graph-card.js
    type: module
    # https://github.com/kalkih/mini-graph-card
#   ----------------------------------------------------------------------------
# Mini Media Player
  - url: /community_plugin/mini-media-player/mini-media-player.js
    type: module
    # https://github.com/kalkih/mini-media-player
#   ----------------------------------------------------------------------------
views:
  - !include lovelace/mobile.yaml
  - !include lovelace/home.yaml
#

but then I added the required resources: and dashboards: section to my configuration.yaml which now looks like this:

[from configuration.yaml]

lovelace:
  mode: yaml
  resources:
  #   ----------------------------------------------------------------------------
  # Mini Graph Card
    - url: local/community/mini-graph-card/mini-graph-card.js
      type: module
      # https://github.com/kalkih/mini-graph-card
  #   ----------------------------------------------------------------------------
  # Mini Media Player
    - url: local/community/mini-media-player/mini-media-player.js
      type: module
      # https://github.com/kalkih/mini-media-player
  #   ----------------------------------------------------------------------------
  dashboards:
    dashboard-mobile: # Needs to contain a hyphen (-)
      mode: yaml
      filename: dashboard-mobile.yaml
      title: Mobile
      icon: mdi:cellphone-settings
      show_in_sidebar: true
      require_admin: false
#  ---------------------------------------------------------------------------

As I move forward, do I need to keep all of my resources definitions in BOTH files or is only one required, and which is preferred? Is there a difference in performance if it is kept in both files, as it passes the config check this way and if a resource is only listed in the ui-lovelace.yaml file and not in the configuration.yaml file will this affect whether it works for YAML generated dashboards or UI-Editor configured dashboards? So far I have not had enough time playing with all the possible combinations to fully appreciate how everything works, but I did see some slowing of responsiveness when using both YAML and System UI dashboard concurrently. My goal is to be fully YAML based mostly for the maintenance benefits of global search and replace using Atom Editor.

** footnote: the above code for [ui-lovelace.yaml] was taken from v104.3 which is my production platform while the [configuration.yaml] code comes from v114.4 on my testing machine. Please note that ALL code on 114.4 is adjusted and compliant with that version.

Only configuration.yaml according to the docs.

@tom_l
Thank you. I literally hate when someone answers with RTFM (which you didn’t), but in this case I should have RTFM. I’m still on 104.4 for various reasons but currently working on all the minor fixes to get upgraded to current. This was just one of those things that I probably did read briefly, but the concept never stuck in my brain. Thank you again for a POLITE and helpful answer.