Almost identical to escape, and you almost definitely want to use escape instead.

Variable

shopping_list = '''Carrots
Honey
Milk
Butter'''

Template with force_escape

{% autoescape off %}
    {{ shopping_list|linebreaks|force_escape }}
{% endautoescape %}

Result

<p>Carrots<br>Honey<br>Milk<br>Butter</p>

Template with escape

{% autoescape off %}
    {{ shopping_list|linebreaks|escape }}
{% endautoescape %}

Result with escape

<p>Carrots<br>Honey<br>Milk<br>Butter</p>

Notice that the <br> tags that are generated with the linebreaks filter are escaped when force_escape is used, but not when escape is used.