Oracle Version:

Oracle Release Number Format:

12.1.0.1.0
 ┬ ┬ ┬ ┬ ┬
 │ │ │ │ └───── Platform-Specific Release Number
 │ │ │ └────────── Component-Specific Release Number
 │ │ └─────────────── Fusion Middleware Release Number
 │ └──────────────────── Database Maintenance Release Number
 └───────────────────────── Major Database Release Number

To know database version query:
seelct version from v$instance;
select banner from v$version;
select comp_name,version,status from dba_registry;

Workflow:
select * from WF_RESOURCES where NAME='WF_VERSION';

Oracle applications:
select release_name from fnd_product_group;

Forms, sql, pls, reports:

adident Header 'filename'

strings file_name |grep $Header

strings -a aprcvmtb.pls | grep 'CREATE'

or use this:
SELECT    'strings $'
       || DECODE (app_short_name,
                  'OFA', 'FA',
                  'SQLGL', 'GL',
                  'SQLAP', 'AP',
                  app_short_name
                 )
       || '_TOP/'
       || subdir
       || '/'
       || filename
       || ' | grep Header'
  FROM ad_files
 WHERE filename = '<your file name>';

Database objects
set long 10000
select text from user_source where name='&package_name' and text like '%$Header%';

SELECT text FROM dba_source WHERE name = 'ARPT_SQL_FUNC_UTIL' AND text LIKE '%Header:%';

select name, text from dba_source where text like '%.pls%' and line < 10;

select VIEW_NAME, TEXT from USER_VIEWS where VIEW_NAME = '&VIEW_NAME';