View file vendor/symfony/error-handler/Resources/views/traces.html.php

<div class="trace trace-as-html" id="trace-box-<?= $index; ?>">
    <div class="trace-details">
        <div class="trace-head">
            <div class="sf-toggle" data-toggle-selector="#trace-html-<?= $index; ?>" data-toggle-initial="<?= $expand ? 'display' : ''; ?>">
                <span class="icon icon-close"><?= $this->include('assets/images/icon-minus-square-o.svg'); ?></span>
                <span class="icon icon-open"><?= $this->include('assets/images/icon-plus-square-o.svg'); ?></span>
                <?php
                $separator = strrpos($exception['class'], '\\');
                $separator = false === $separator ? 0 : $separator + 1;

                $namespace = substr($exception['class'], 0, $separator);
                $class = substr($exception['class'], $separator);
                ?>
                <?php if ('' === $class) { ?>
                    </br>
                <?php } else { ?>
                    <h3 class="trace-class">
                        <?php if ('' !== $namespace) { ?>
                            <span class="trace-namespace"><?= $namespace; ?></span>
                        <?php } ?>
                        <?= $class; ?>
                    </h3>
                <?php } ?>
                <?php if ($exception['message'] && $index > 1) { ?>
                    <p class="break-long-words trace-message"><?= $this->escape($exception['message']); ?></p>
                <?php } ?>
            </div>
        </div>

        <div id="trace-html-<?= $index; ?>" class="sf-toggle-content">
        <?php
        $isFirstUserCode = true;
        foreach ($exception['trace'] as $i => $trace) {
            $isVendorTrace = $trace['file'] && (false !== mb_strpos($trace['file'], '/vendor/') || false !== mb_strpos($trace['file'], '/var/cache/'));
            $displayCodeSnippet = $isFirstUserCode && !$isVendorTrace;
            if ($displayCodeSnippet) {
                $isFirstUserCode = false;
            } ?>
            <div class="trace-line <?= $isVendorTrace ? 'trace-from-vendor' : ''; ?>">
                <?= $this->include('views/trace.html.php', [
                    'prefix' => $index,
                    'i' => $i,
                    'trace' => $trace,
                    'style' => $isVendorTrace ? 'compact' : ($displayCodeSnippet ? 'expanded' : ''),
                ]); ?>
            </div>
            <?php
        } ?>
        </div>
    </div>
</div>