Here are the classes, structs, unions and interfaces with brief descriptions:

[detail level 1234]

acl_selectors
Friendica
friendica-to-smarty-tpl
Hubzilla
Import
Import	Class Import
updatetpl
util
Zotlabs
Access
AccessList	AccessList class
PermissionLimits
PermissionRoles	PermissionRoles class
Permissions	Extensible permissions
Daemon
Addon
Checksites
Cli_suggest
Cron
Cron_daily
Cron_weekly
Cronhooks
CurlAuth
Deliver
Deliver_hooks
Directory
Expire
Externals
Gprobe
Importdoc
Importfile
Master
Notifier
Onedirsync
Onepoll
Poller
Queue
Ratenotif
Thumbnail
Extend
Hook	Hook class
Identity
BasicId
BasicId
ProfilePhoto
ProfilePhoto
Lib
AbConfig
AConfig
ActivityStreams	ActivityStreams class
Api_router
Apps
Cache
Chatroom	A class with chatroom related static methods
Config
DB_Upgrade
Enotify	File with functions and a class for generating system and email notifications
ExtendedZip
IConfig
JSalmon
LDSignatures
MarkdownSoap
NativeWiki
NativeWikiPage
PConfig	Class for handling channel specific configurations
Permcat
PermissionDescription
ProtoDriver
SConfig	Account configuration storage is built on top of the under-utilised xconfig
SuperCurl	Wrapper for z_fetch_url() which can be instantiated with several built-in parameters and these can be modified and re-used. Useful for CalDAV and other processes which need to authenticate and set lots of CURL options (many of which stay the same from one call to the next)
System
Techlevels
ThreadItem
ThreadStream
XConfig	Class for handling observer's config
ZotDriver
Module
Admin
Account_edit
Accounts
Channels	Admin Module for Channels
Dbsync
Features
Logs
Plugins
Profs
Queue
Security
Site
Themes	Admin area theme settings
Settings
Account
Channel
Display
Featured
Features
Oauth
Permcats
Tokens
Achievements
Acl
Admin	Admin area
Api
Appman
Apporder
Apps
Article_edit
Articles
Attach
Authorize
Block
Blocks
Bookmarks
Branchtopic
Cal
Card_edit
Cards
Cdav
Changeaddr
Channel	Channel Controller
Chanview
Chat
Chatsvc
Cloud	Cloud Module
Cloud_tiles
Common
Connect
Connections
Connedit
Contactgroup
Cover_photo
Dav
Defperms
Directory
Dirsearch
Display
Dreport
Editblock
Editlayout
Editpost
Editwebpage
Embedphotos
Events
Fbrowser
Feed
Fhublocs
File_upload
Filer
Filerm
Filestorage
Follow
Getfile
Group
Hcard
Help
Home
Hostxrd
Hq
Impel
Import	Module for channel import
Import_items	Module for importing items
Invite
Item
Lang
Layouts
Like
Linkinfo
Lockview
Locs
Login
Logout
Lostpass
Magic
Mail
Manage
Menu
Message
Mitem
Moderate
Mood
Network
New_channel
Nojs
Notes
Notifications
Notify
Oembed
Oep
Oexchange
Ofeed
Online
Owa
Page
Pconfig
Pdledit
Permcat
Photo
Photos
Ping	Ping Controller
Poco
Poke
Post	Post module
Prate
Pretheme
Probe
Profile
Profile_photo
Profiles
Profperm
Pubsites
Pubstream
Randprof
Rate
Ratings
Ratingsearch
Rbmark
React
Regdir
Register
Regmod
Regver
Removeaccount
Removeme
Rmagic
Rpost
Search
Search_ac
Service_limits
Settings
Setup	Initialisation for the setup module
Share
Sharedwithme
Siteinfo
Sitelist
Smilies
Snap	Fires up the SabreDAV server
Sources
Sslify
Starred
Subthread
Suggest
Tagger
Tagrm
Tasks
Theme_info
Thing
Toggle_mobile
Toggle_safesearch
Token
Uexport
Update
View
Viewconnections
Viewsrc
Wall_attach
Wall_upload
Webfinger
Webpages
Well_known
Wfinger
Wiki
Xchan
Xpoco
Xrd
Xref
Zfinger
Zotfeed
Zping
Render
Comanche	Comanche Page Description Language
SimpleTemplate
SmartyInterface
SmartyTemplate
TemplateEngine	Interface for template engines
Theme
Storage
BasicAuth	Authentication backend class for DAV
Browser	Provides a DAV frontend for the webbrowser
CalDAVClient
Directory	RedDirectory class
File	This class represents a file in DAV
GitRepo
Text
Tagadelic
Theme
RedbasicConfig
Thumbs
Epubthumb
Mp3audio
Pdf
Text
Video
Web
CheckJS
Controller
HTTPHeaders
HttpMeta
HTTPSig
Router
Session	This file includes session related functions
SessionHandler
SubModule
WebServer
Widget
Activity
Admin
Affinity
Album
Appcategories
Appcloud
Archive
Bookmarkedchats
Catcloud_wall
Categories
Cdav
Chatroom_list
Chatroom_members
Clock
Collections
Common_friends
Conversations
Cover_photo
Design_tools
Dirsort
Dirtags
Eventstools
Filer
Findpeople
Follow
Forums
Fullprofile
Helpindex
Hq_controls
Item
Mailmenu
Menu_preview
Notes
Notifications
Photo
Photo_albums
Photo_rand
Portfolio
Profile
Pubsites
Random_block
Rating
Savedsearch
Settings_menu
Shortprofile
Sitesearch
Suggestedchats
Suggestions
Tagcloud
Tagcloud_wall
Tasklist
Vcard
Website_portation_tools
Wiki_list
Wiki_page_history
Wiki_pages
Zcard
Zot
Auth
DReport
Finger	Finger
IHandler
Receiver
Verify
ZotHandler
zotsh
CommandNotFound
ZotSH
App	Our main application structure for the life of this page
DBA
dba_driver	Abstract database driver class
dba_mysql
dba_mysqli
dba_pdo
dba_postgres
miniApp
photo_driver
photo_gd
photo_imagick
ZotOAuth1
ZotOAuth1DataStore