You need a schema of the type config_entity
.
See for example the one for the node type config entity:
/node/config/schema/node.schema.yml:
node.type.*:
type: config_entity
label: 'Content type'
mapping:
name:
type: label
label: 'Name'
type:
type: string
label: 'Machine-readable name'
description:
type: text
label: 'Description'
help:
type: text
label: 'Explanation or submission guidelines'
new_revision:
type: boolean
label: 'Whether a new revision should be created by default'
preview_mode:
type: integer
label: 'Preview before submitting'
display_submitted:
type: boolean
label: 'Display setting for author and date Submitted by post information'
Choose for fields you want to make translatable the types label
and text
. See also D8 How to create custom configurational form translatable?