What is Ansible's config equivalent of `--vault-password-file`?

According the help of ansible-playbook one could use --user=REMOTE_USER to define the ssh user, but one could also define ansible_ssh_user: REMOTE_USER in either the host- or group_vars.

Question

What variable need to be defined in either the group- or host_vars directory to prevent that --vault-password-file has to be defined while running ansible-playbook?

Attempts

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When ansible_vault_password_file: ~/.vault_pass.txt is defined in the config the decryption fails:

ERROR! Decryption failed on /path/to/vault

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No associated vault variables was found in this documentation

Here is the definition:

DEFAULT_VAULT_PASSWORD_FILE = get_config(p, DEFAULTS, 'vault_password_file', \
'ANSIBLE_VAULT_PASSWORD_FILE', None, value_type='path')

This means that you either put in ansible.cfg or playbook:

vault_password_file: ~/.vault_pass.txt

Or in your shell defined this variable:

export ANSIBLE_VAULT_PASSWORD_FILE=~/.vault_pass.txt

StackExchange DevOps Q#703, answer score: 15