find-tag-marker-ring-length

find-tag-marker-ring-length is a variable defined in `etags.el'.
Its value is

16

• This variable is an alias for `xref-marker-ring-length'.
• This variable is obsolete since 25.1;
  use `xref-marker-ring-length' instead.

Documentation:
Length of the xref marker ring.

You can customize this variable.