Here is some indication how to customize the footer text “ownCloud – web services under your control”, title, etc. This can be achieved easily editing the following file under your ownCloud root folder :
/lib/private/defaults.php
Then, locate the following starting at line number 31 :
$this->defaultEntity = "ownCloud"; /* e.g. company name, used for footers and copyright notices */
$this->defaultName = "ownCloud"; /* short name, used when referring to the software */
$this->defaultTitle = "ownCloud"; /* can be a longer name, for titles */
$this->defaultBaseUrl = "https://www.owncloud.org";
$this->defaultSyncClientUrl = "https://owncloud.org/sync-clients/";
$this->defaultDocBaseUrl = "http://doc.owncloud.org";
$this->defaultDocVersion = $version[0] . ".0"; // used to generate doc links
$this->defaultSlogan = $this->l->t("web services under your control");
$this->defaultLogoClaim = "";
$this->defaultMailHeaderColor = "#1d2d44"; /* header color of mail notifications */
What you are looking to change would be :
$this->defaultEntity = "ownCloud"; /* e.g. company name, used for footers and copyright notices */
$this->defaultName = "ownCloud"; /* short name, used when referring to the software */
$this->defaultTitle = "ownCloud"; /* can be a longer name, for titles */
$this->defaultBaseUrl = "https://www.owncloud.org";
$this->defaultSlogan = $this->l->t("web services under your control");