knowledge/document_url/static/src/xml/url.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!-- Copyright 2018 Tecnativa - Ernesto Tejeda
     Copyright 2021 Tecnativa - Víctor Martínez
     License AGPL-3.0 or later (https://www.gnu.org/licenses/agpl). -->
<templates>
    <t t-inherit="mail.Chatter" t-inherit-mode="extension">
        <xpath expr="//AttachmentList//..//FileUploader/t" position="replace">
            <t t-set-slot="toggler">
                <div class="d-flex mx-auto">
                    <button
                        class="btn btn-link"
                        type="button"
                        t-att-disabled="!state.thread.hasWriteAccess"
                    >
                        <i class="fa fa-plus-square" />
                        Attach files
                    </button>
                    <button
                        class="btn btn-link"
                        type="button"
                        t-att-disabled="!state.thread.hasWriteAccess"
                        t-on-click="_onAddUrl"
                    >
                        <i class="fa fa-plus-square" />
                        Add URL
                    </button>
                </div>
            </t>
        </xpath>
    </t>
    <t t-inherit="mail.AttachmentList" t-inherit-mode="extension">
        <xpath
            expr="//div[hasclass('o-mail-AttachmentCard-aside')]//button[@title='Download']"
            position="after"
        >
            <button
                class="btn d-flex justify-content-center align-items-center w-100 h-100 rounded-0"
                t-attf-class="bg-300"
                t-on-click="() => window.open(attachmentUrl, '_blank')"
                title="Open"
                t-if="attachment.mimetype === 'application/link'"
                target="_blank"
            >
                <i class="fa fa-link" role="img" aria-label="Open" />
            </button>
        </xpath>
        <xpath
            expr="//div[hasclass('o-mail-AttachmentCard-image')]"
            position="attributes"
        >
            <attribute
                name="t-if"
            >attachment.mimetype !== 'application/link'</attribute>
        </xpath>
        <xpath expr="//div[hasclass('o-mail-AttachmentCard-image')]" position="before">
            <a
                class="o_Attachment_url_ico o_image flex-shrink-0 m-1"
                t-att-href="attachmentUrl"
                target="_blank"
                t-if="attachment.mimetype === 'application/link'"
            >
                <i class="fa fa-link fa-2x" />
            </a>
        </xpath>
    </t>
</templates>