I did this in SQL Plus
SQL> set autotrace traceonly explain
SQL> alter session set events = '10046 trace name context forever, level 8';
Session altered.
SQL> select * from scott.emp;
Execution Plan
----------------------------------------------------------
Plan hash value: 3956160932
--------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time |
--------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | 14 | 518 | 3 (0)| 00:00:01 |
| 1 | TABLE ACCESS FULL| EMP | 14 | 518 | 3 (0)| 00:00:01 |
--------------------------------------------------------------------------
SQL> exit
and you'll find this in the trace file
=====================
PARSING IN CURSOR #1265379229168 len=23 dep=0 uid=107 oct=3 lid=107 tim=667341359539 hv=52404428 ad='7ff9f65780e8' sqlid='ggqns3c1jz86c'
select * from scott.emp
END OF STMT
PARSE #1265379229168:c=15625,e=6027,p=0,cr=103,cu=0,mis=1,r=0,dep=0,og=1,plh=3956160932,tim=667341359539
WAIT #1265379229168: nam='SQL*Net message to client' ela= 2 driver id=1111838976 #bytes=1 p3=0 obj#=-1 tim=667341359623
WAIT #1265379229168: nam='SQL*Net message from client' ela= 144 driver id=1111838976 #bytes=1 p3=0 obj#=-1 tim=667341359798
CLOSE #1265379229168:c=0,e=4,dep=0,type=0,tim=667341359833
=====================
PARSING IN CURSOR #1265379229168 len=45 dep=0 uid=107 oct=7 lid=107 tim=667341360021 hv=349105966 ad='7ff9f9278b10' sqlid='g72kdvcacxvtf'
DELETE FROM PLAN_TABLE WHERE STATEMENT_ID=:1
END OF STMT
PARSE #1265379229168:c=0,e=162,p=0,cr=0,cu=0,mis=1,r=0,dep=0,og=1,plh=0,tim=667341360020
EXEC #1265378284408:c=0,e=19,p=0,cr=0,cu=0,mis=0,r=0,dep=1,og=4,plh=3845132125,tim=667341360175
FETCH #1265378284408:c=0,e=16,p=0,cr=2,cu=0,mis=0,r=0,dep=1,og=4,plh=3845132125,tim=667341360212
CLOSE #1265378284408:c=0,e=1,dep=1,type=3,tim=667341360234
EXEC #1265378276472:c=0,e=15,p=0,cr=0,cu=0,mis=0,r=0,dep=1,og=4,plh=2570921597,tim=667341360266
FETCH #1265378276472:c=0,e=5,p=0,cr=2,cu=0,mis=0,r=0,dep=1,og=4,plh=2570921597,tim=667341360283
CLOSE #1265378276472:c=0,e=1,dep=1,type=3,tim=667341360297
So it looks like we clean up any entries in the plan_table.