The designer says

Cookie	Provider	Description	Expires
COPAUTH	OCLC	The cookie stores a successful login.	10 years after creation
EU_LAW_INFO	OCLC	Is set when the user has acknowledged the usage of cookies in OPEN.	10 years after creation
.ASPXANONYMOUS	DNN	The cookie stores an unique ID für anonymous users.	approximately 70 days
.DOTNETNUKE	DNN	A DNN cookie which is created during login.	Session
ASP.NET_SessionId	ASP.NET	Identifies the session of ASP.NET.	Session
authentication	OCLC	Saves the registration way of the patron. DNN (= DNN Login), COP (= OPEN Login) "" (= Patron is not logged in)	Session
dnn_IsMobile	DNN	The cookie stores whether the user uses a mobile device (e.g. a smartphone).	Session
languague	DNN	The cookie stores the currently set language (e.g. de-DE).	Session
LastPageId	DNN	The cookie stores the ID (TabID) of the last visited tab.	Session
__RequestVerificationToken	DNN	The cookie offers protection against cross-site attacks.	Session
SplashPageView	DNN	The cookie controls the single display of the welcome page.	Session
RepeaterCategories, RepeaterGroup	DNNGo	Cookies of the DNN module xPlugin, for layout configuration.	Session

Cookie	Provider	Description	Expires
GOOGLE_ANALYTICS_INFO	OCLC	The cookie is set when the user has acknowledged the usage of the tracking tool Google Analytics.	1 year
_ga, _ga__<container-id>	Google Analytics	The cookie _ga saves the Google Analytics-Client-ID in order to distinguish users, _ga__<container-id> is used to persist session state (provided the user has acknowledged the tool, please refer to cookie GOOGLE_ANALYTICS_INFO).	2 years
_Module_359_Survey_0_, AppearanceSecurityOptions, CSVExportOptions	DNN	These cookies are used by the optional 3rd party DNN module Survey.	until 31.12.9999, 20 minutes, 20 minutes

Cookie	Provider	Description	Expires
List of all settings cookies of OPEN:	OCLC	The cookies control the unfolded/closed - status of the different settings sections as well as the visibility of the headers.	Session
StayInEditMode	DNN	The cookie controls the edit mode of the page.	Session
cem_pending, CEM_CallbackData, CEM_ExistingModule, CEM_NewModuleId	DNN	These cookies are saved when adding or duplicating a module during edit mode.	Session