Example context consumer

consumer-symbol.js

import { LightningElement } from 'lwc';
import { I18nContextSymbol } from 'i18n/context';

// https://vuejs.org/guide/components/provide-inject.html#working-with-symbol-keys
export default class Foo extends LightningElement {
    static context = {
        [I18nContextSymbol]: { from: '18n' }
    };

    connectedCallback() {
        console.log(this.i18n)
    }
}

consumer.js

import { LightningElement } from 'lwc';

export default class Foo extends LightningElement {
    static context = [
        'i18n',
    ];

    connectedCallback() {
        console.log(this.i18n)
    }
}