The following markers could be set:
// General markers
###URL_SELF###
###FORM_NAME###
###FORM_ID###
###INFO###
###HIDDEN###
###SUBMIT###
###SUBMIT_VALUE###
###CHARSET###
###ANCHOR###
// Show all messages of all fields as list
###MESSAGES###
// Show inline messages for each field
###MSG_###
// Add error class to each field
###ERR_###
// Show the value of input fields
###VALUE_###
// Set state of a checkbox
###CHECKED_###
// Set state of a radio button
###CHECKED__[######]###
// Set state of a select option
###SELECTED__[######]###
// Show labels for the input fields
###LABEL_###
// Show required symbol for the input fields
###REQUIRED_###
// Show your own markers (define via TypoScript - see manual)
######
// Show your own locallang labels (see manual)
###LLL:###
// Show page information
###PAGE:###
// Show plugin information
###PLUGIN:###
// Show user information
###USER:###
// Show captcha (see manual)
###CAPTCHA_DATA###
###CAPTCHA_FILE###
###SR_FREECAP_NOTICE###
###SR_FREECAP_CANT_READ###
###SR_FREECAP_IMAGE###
###SR_FREECAP_ACCESSIBLE###
###CAPTCHA_FIELD###