Hello Jmartsch and Wanze,
It is great to be assisted, thank you ?. I changed my config to have the global file field empty. So I put all my *.twig files in the views directory. I created partials directory for parts included in base.twig.
So I keep home.twig and engagement.twig in views.
in home.twig I have
{% block home %}
<div id="corps"> <div id="titres">
<div id="titre">{{ page.title }}</div>
</div>
<div class="hr"></div>
<br>
{% block engagement %}{% endblock %}
{% endblock %}
In engagement.twig, I have
{% extends 'home.twig' %}
{% block engagement %}
<p>His cognitis Gallus ut serpens adpetitus telo vel saxo iamque spes extremas opperiens et succurrens saluti suae quavis ratione colligi omnes iussit armatos et cum starent attoniti, districta dentium acie stridens adeste inquit viri fortes mihi periclitanti vobiscum.</p>
<p>Mensarum enim voragines et varias voluptatum inlecebras, ne longius progrediar, praetermitto illuc transiturus quod quidam per ampla spatia urbis subversasque silices sine periculi metu properantes equos velut publicos signatis quod dicitur calceis agitant, familiarium agmina tamquam praedatorios globos post terga trahentes ne Sannione quidem, ut ait comicus, domi relicto. quos imitatae matronae complures opertis capitibus et basternis per latera civitatis cuncta discurrunt.</p>
{% endblock %}
But still engagement block is not displayed.