This is just an extra information injected in PeerTube HTML that is required by Twitter/X. If you don't have a Twitter/X account, just leave the default value.
This is an <x id="START_TAG_STRONG" ctype="x-strong" equiv-text="<strong>"/>import<x id="CLOSE_TAG_STRONG" ctype="x-strong" equiv-text="</strong>"/> tool and not a migration tool. It's the reason why data (like channels or videos) is duplicated and not moved from your previous PeerTube website.
This instance allows registration. However, be careful to check the <x id="START_LINK" ctype="x-a" equiv-text="<a class="link-orange terms-anchor" (click)="onTermsClick($event, instanceInformation)" href='#'>"/>Terms<x id="CLOSE_LINK" ctype="x-a" equiv-text="</a>"/><x id="START_LINK_1" equiv-text="<a class="terms-link" target="_blank" routerLink="/about/instance" fragment="terms">"/>Terms<x id="CLOSE_LINK" ctype="x-a" equiv-text="</a>"/> before creating an account. You may also search for another instance to match your exact needs at: <x id="START_LINK_2" equiv-text="<a class="link-orange" href="https://joinpeertube.org/instances" target="_blank" rel="noopener noreferrer">"/>https://joinpeertube.org/instances<x id="CLOSE_LINK" ctype="x-a" equiv-text="</a>"/>.
The video quota only takes into account the size of <x id="START_TAG_STRONG" ctype="x-strong" equiv-text="<strong>"/>uploaded<x id="CLOSE_TAG_STRONG" ctype="x-strong" equiv-text="</strong>"/> videos, not transcoded files or user export archives (which may contain video files).