Configurations in scripts

Configuration usually depends on module, for special template developer or backend developer configuration.
For regular admins configuration is available in admin->settings
Below you can read more about some special configurations for template developers and other:

field_file_upload_enabled – for template developers only, define if file upload is supported by template
dependent_treefield – for template developers only, define if treefield is supported by template
enable_lang_autodetection – autodetect language based on browser lang

orderby_datemodified_enabled – for template developers only, define if datemodified is supported by template
orderby_daterenew_enabled – for template developers only, define if datemodified is supported by template
additional_typeahead_address – for template developers only, define if address in typeahead is supported by template

logout_redirection_uri – for template developers only, define logout url, usually for special configurations
page_slideshow_enabled – for template developers only, define if page slideshow is supported by template
per_page_profile – for template developers only, define how many listings is visible per page on profile page, depends on specific template design
disable_faq_for_agent – for backend developers only, define if faq links are visible for agents also

Related to third parity modules/addons and available in modules instructions after module purchase:

events_qr_confirmation – special configuration for events attention confirmation
multi_domains_enabled – multi-language domains, different domain for different language
booking_multi_reservations – for booking module, enable multiple reservations for admin
booking_import_enabled – for booking module, enable import
add_multiple_rates_summer_enabled – for booking module, enable summer rates
agent_profile_direct – show all listings on agent page if agent is accesses by direct page link, not via homepage for example
transitions_id_enabled – using on imports usually, to detect same listings on update
loaded_template_config – template identification for config loaded
invoice_auto_activate – mark invoice as paid by user payer, not by admin
price_by_purpose – retired configuration, for old templates
csv_import_enabled – for import module
import_foursquare – for import module
import_google_places – for import module
add_multiple_rates_summer_enabled – for booking module

quick_reply_enabled – enable inquiry reply via dash in admin
enable_additional_roles – enable user types like admin agent, agent limited
dropdown_register_enabled – option to enable user type selection on registration form
terms_link – link to terms, for gdpr also, example:
$config['terms_link'] = 'http://www.google.com?q=agree+terms#q=agree+terms';